If only the same could be said of electric bills. The price of U.S. solar power has dropped a whopping 70 percent since 2009, even as panels get smarter. The figure, cited in a report this week from Lawrence Berkeley National Laboratory, coincides with SolarCity’s debut on Friday of what it calls the world’s most efficient rooftop solar panel. The largest residential solar installer in the U.S. says its module can produce 38 percent more power than a standard one, yet costs less to produce power. Not bad for an industry that had no large-scale U.S. presence just a decade ago. Photovoltaic panels currently contribute only about 1 percent of all electricity, but lower costs are helping fuel the expansion of large, utility-size projects. As historic UN climate talks near, solar’s latest strides are key in the worldwide race to slash carbon emissions by paring back dependence on fossil fuels. “It is quite remarkable and exciting when you have this amount of growth, and an industry goes from basically being a hobby to a mainstream industry, “ says Peter Rive, SolarCity’s co-founder and chief technology officer. (Rive’s cousin and SolarCity’s chairman, Elon Musk, is also seeking to boost solar’s appeal to utilities with his recently launched Tesla battery system.) The company’s new panel “takes solar a step further to be a cheaper energy source without requiring federal incentives such as the investment tax credit, “ Rive says. That credit currently returns 30 percent of a solar system’s cost to the buyer. Its looming expiration at the end of next year has lent urgency to the industry’s efforts to bring down prices. The Berkeley Lab report predicts a “frenzied pace of construction over the next 15 months“. Contracts to buy power from large-scale solar projects average 5 cents per kilowatt hour, according to the report, while electricity prices on the wholesale market run from 3 cents to 6 cents per kilowatt hour. The plunging cost of solar hasn’t translated to lower electric bills so far: in most regions — even ones with big solar plants — people are paying a bit more for power than they did a few years ago, because many different factors go into determining retail electricity rates. Rather, the trend means more of that power might be coming from carbon-free sources that are less subject to the price shocks of fossil fuels. “While it’s difficult to make a direct cost comparison between new solar projects and existing fossil fuel power plants, “ says report co-author Mark Bolinger, “Solar is getting to a point where it can compete with coal and natural gas for electricity in some places.“ “Just a few years ago, that was much more of a stretch, “ he says. The falling price of power from large-scale solar projects reflects the lower cost of building them. The report notes that cost fell by more than 50 percent between 2009 and 2014. At the same time, solar farms have seen a “notable improvement“ in how much power they put out, thanks to smarter siting and better technology. SolarCity is aiming to apply its own gains in efficiency and cost to the residential market when it begins production at its 1-gigawatt facility in Buffalo, New York, in early 2017. Its new rooftop panel, which earned a rating of 22.04 percent efficiency in a third-party certification test, surpasses an earlier record set by SunPower, which has a high-efficiency model rated at 21.5 percent. Another trend Bolinger called “encouraging“: Solar’s reach is expanding. Most development has been centered in the Southwest, but Bolinger says big solar power contracts are cropping up in Alabama, Arkansas, Florida, and Georgia — states that “haven’t seen much solar development in the past to speak of. Of course, prices won’t keep tumbling so steeply in the years ahead. What we might see instead, Bolinger says, is that the market for solar will just continue to expand.

Twitter Fiction In today’s lecture, I’d like to talk about telling stories online. I. In the 1930s, radio 【T1】______and connected people. 【T1】______ A. Radio emanated stories. B. Radio evolved its own 【T2】______. 【T2】______ - e.g. episodes: combining 【T3】______and written fiction 【T3】______ II. Today’s new medium: 【T4】______ 【T4】______ A. Thousands of Twitter users. B. People learn how to tell their stories. - We are in the frontier for 【T5】______ 【T5】______ - New formats of storytelling will start from 【T6】______ 【T6】______ III. 【T7】______ 【T7】______ A. Jennifer Egan wrote “Black Box“. - Jennifer started a New Yorker fiction account. - The New Yorker 【T8】______over 600 tweets. 【T8】______ - It can be called 【T9】______. 【T9】______ - There were multiple ways to experience the fiction. - You could scroll back through it. - You could watch it live with 【T10】______of waiting for the next line. 【T10】______ B. Elliott Holt wrote “Evidence“. - It began with an Elliott’s voice. - We heard the voices from other characters. - A story was created from 【T11】______. 【T11】______ - Twitter became a 【T12】______mechanism. 【T12】______ C. People played with 【T13】______. 【T13】______ - e.g. “West Wing“ Twitter has fictional characters that engage with 【T14】______. 【T14】______ - They comment on politics and they’re all Democrats. IV. Conclusion: real-time storytelling online blurs the lines between 【T15】______. 【T15】______Twitter Fiction Good morning, everyone. In today’s lecture, I’d like to talk about telling stories online. So in my free time outside of Twitter, I experiment a little bit with telling stories online, experimenting with what we can do with new digital tools. And in my job at Twitter, I actually spent a little bit of time working with authors and storytellers as well, helping to expand out the bounds of what people are experimenting with. And I want to talk through some examples today of things that people have done that I think are really fascinating using flexible identity on the web and blurring the lines between fact and fiction. But first, I want to start and go back to the 1930s. Long before a little thing called Twitter, radio brought us broadcasts and connected millions of people to single points of broadcast. And from those single points emanated stories. Some of them were familiar stories. Some of them were new stories. And for a while they were familiar formats, but then radio began to evolve its own unique formats specific to that medium. Think about episodes that happened live on radio. Combining the live play and the serialization of written fiction, you get this new format. And the reason why I bring up radio is that I think radio is a great example of how a new medium defines new formats which then define new stories. Today, we have an entirely new medium to play with, which is this online world. There are thousands upon thousands of Twitter users. Every single one of these points is its own broadcaster. We’ve gone to this world of many to many, where access to the tools is the only barrier to broadcasting. And I think that we should start to see wildly new formats emerge as people learn how to tell stories in this new medium. I actually believe that we are in a wide open frontier for creative experimentation, if you will, that we’ve explored and begun to settle this wild land of the Internet and are now just getting ready to start to build structures on it, and those structures are the new formats of storytelling that the Internet will allow us to create. I believe this starts with an evolution of existing methods. The short story, for example, people are saying that the short story is experiencing a renaissance of sorts thanks to e-readers, digital marketplaces. Here I would like to cite some examples of this new type of fiction. This is an example of short story by the author Jennifer Egan called “Black Box“. Egan convinced The New Yorker to start a New Yorker fiction account from which they could tweet all of these lines that she created. Egan wrote each individual tweet manually in the storyboard sketchbook and those tweets ended up becoming over 600 of them. Then they were serialized by The New Yorker. Every night, at 8 p.m., you could tune in to a short story from The New Yorker’s fiction account. I think that’s pretty exciting and it can be called “tune-in literary fiction“. The experience of Egan’s story, of course, like anything on Twitter, there were multiple ways to experience it. You could scroll back through it, but interestingly, if you were watching it live, there was this suspense that built because the actual tweets were coming at a pretty regular clip, but in this case, The New Yorker was sending you bit by bit, and you had this suspense of waiting for the next line. Another great example of fiction and the short story on Twitter, Elliott Holt is an author who wrote a story called “Evidence“. It began with this tweet: “On November 28 at 10:13 p.m., a woman identified as Miranda Brown, 44, of Brooklyn, fell to her death from the roof of a Manhattan hotel.“ It begins in Elliott’s voice, but then Elliott’s voice recedes, and we hear the voices of Elsa, Margot and Simon, characters that Elliott created on Twitter specifically to tell this story, a story from multiple perspectives leading up to this moment at 10:13 p.m. when this woman falls to her death. These three characters brought an authentic vision from multiple perspectives. Elliott captured that voice and she had multiple characters and it happened in real time. Interestingly, though, it wasn’t just Twitter as a distribution mechanism. It was also Twitter as a production mechanism. Elliott told me later she wrote the whole thing with her thumbs. She laid on the couch and just went back and forth between different characters tweeting out each line, line by line. So through this format she had created multiple perspectives in a single story on Twitter. As you begin to play with flexible identity online, it gets even more interesting as you start to interact with the real world. All of these are rapid iterations on a theme. They are creative people experimenting with the bounds of what is possible in this medium. You look at something like “West Wing“ Twitter, in which you have these fictional characters that engage with the real world. They comment on politics, they cry out against the evils of Congress. Keep in mind, they’re all Democrats. As a conclusion, with real-time storytelling, blurring the lines between fact and fiction, the real world and the digital world, flexible identity, anonymity, these are all tools that we have accessible to us, and I think that they’re just the building blocks. They are the bits that we use to create the structures, the frames. That then would become our settlements on this wide open frontier for creative experimentation.

(I): Tell me more about how this collaboration between the English students and the computer science students worked. (S): I had some historians come in and talk to the academic English students about local history. During these discussions, students asked questions about areas of interest. From there, students would research further and then write their stories. They had several weeks to do so. The English teacher gave them the option of writing in pairs, so they could be very creative. Once the stories were written, they were graded and then sent back to the students for revisions. We then picked the best stories. It was really a great project thus far. Next, we had a third-grade teacher look the stories over to make sure that the terminology wasn’t too tough. After the stories were returned, they were sent to a historian who picked them apart detail by detail to make sure everything in the story was historically accurate. For example, “lights“ was changed to “gaslights, “ and numbers were made more exact. With the Babe Ruth/Cricket Field stories, we worked with Elaine Conrad, one of our local historians. She found newspaper articles about the Babe Ruth ball game at Cricket Field that revealed all kinds of great details, like the number of people that attended the game, what street the homerun was hit to, and so on. (I): And once the stories had been written, your computer science students had the job of illustrating them and making them into webpages? (S): Once I got the stories, I passed them out to groups of three to four students. At this point, I probably had about five stories that were really good. Students were given the assignment to associate pictures with the stories. My students were told that the stories were going to be put on the Internet for young readers. The stories needed to have color, animation, and anything that would draw the attention of a young reader. Webpages were created using FrontPage (a software program for designing webpages). Students did all the tasks that go along with webpage creation. Since so many groups worked on each story, I brought in some elementary students and let them pick the webpages that they liked the best. That first year we posted four stories on the Internet. It took us a whole year to do all this—research the stories, write the stories, illustrate the stories, and make the webpages. (I): Now, you weren’t always a computer science teacher, right? (S): Well, my background is mathematics, but back in the early 80s, I was the only teacher in my school district who had taken any computer classes. When my administrators told me that they wanted me to start teaching computer classes, I said, “No, I hate computers. I don’t want to do it.“ Not really given a choice, I started teaching something that I absolutely hated but soon came to love teaching computer classes. I originally started with a few computer classes, but eventually they took over my whole day. So, I’m no longer a mathematics teacher but instead, a computer science teacher. This is the end of Part Two of the interview. Questions 6 to 10 are based on what you have just heard. Question Six What did they do during the writing part in the project? Question Seven Why did Irene raise the example of Babe Ruth/Bricket Field story? Question Eight What did they do in the process of putting the stories on the Internet? Question Nine What did Irene think of computers before she taught it? Question Ten What can be concluded from the interview? They invited some historians to introduce the local history. Students could choose to write in pairs. A third-grade teacher checked the special terms in their writing. All the above.

“Superbugs“ is a nickname that’s probably too playful for the subject it covers. It refers to new strains of bacteria that have evolved to become untreatable with any existing drugs, immune to the antibiotics that have been one of the pillars of modern medicine and allowed us all to survive infections that used to kill. In the US alone, each year these superbugs infect more than 2 million people and kill at least 23, 000. Globally, the World Health Organization called antibiotic resistance a serious threat that is “no longer a prediction for the future, it is happening right now in every region of the world and has the potential to affect anyone, of any age, in any country“. “Without urgent, coordinated action by many stakeholders, the world is headed for a post-antibiotic era, in which common infections and minor injuries which have been treatable for decades can once again kill, “ said Dr. Keiji Fukuda, WHO’s assistant director-general for health security. In the race against superbugs’ Darwinian evasion, however, scientists have come up with few new kinds of antibiotics that are effective against scourges such as drug-resistant tuberculosis and staphylococcus or untreatable gonorrhea. But maybe there’s another way. Enter Timothy Lu, associate professor of biological and electrical engineering at MIT, was born in the US and at 10 moved back to his family home in Taiwan where he spent his adolescence before going to MIT and Harvard. Lu and his team report in the latest issue of Nature Biotechnology two new ways to turn the tables on superbugs. “Antibiotic resistance is going up and at the same time we aren’t finding very many new antibiotics to treat the problem, “ Lu said. The primary issue, he said, is that antibiotics are like “a very blunt sword“. In many cases when someone has an infection, there is only one type of bacteria that is causing the disease, but there are many billions and trillions of good bacteria living inside of us. “So when we take antibiotics, we’re kind of blasting everybody, when we’re only trying to kill that one guy, “ he said. That in turn leads to risks of increasing resistance or other infections where other bad bacteria grow in the absence of the good. Lu and his team took a different approach. “We developed a method that allows you to very selectively and efficiently kill bacteria that basically contain bad genes, and only those, “ he said. The technique is called “gene editing“ and it could change more than just the battle against superbugs. Lu said he thinks of DNA as “the software of life“, the genes in our body — or in bacteria — determine how everything functions. Everything follows its genetic code. “What’s been really difficult until recently has been if you want to go in and modify DNA, it’s been quite challenging to do that, “ he said. “But recent developments in gene-editing allow us to design systems that go in and cut out genes you don’t want or change a gene into another gene. Basically you can read and write DNA much more efficiently than you could before“. DNA is like a very long piece of tape and we have the ability now to go in and cut and replace and overwrite. The tools are molecules — proteins, or other pieces of DNA or RNA — that act like machines. Think of it as “designer genetic editing“. The tools have been developed not only for bacterial systems and yeast but also for mammalian and human cells. “It’s really been a big revolution over the last few years, “ he said. His team developed two gene-editing systems that sabotage superbugs by using their own immune systems, the weapons they use to protect themselves, against them. One infiltrates, snips the DNA and destroys the cell outright; the other re-codes the antibiotic resistance they’ve evolved so they’re once again susceptible to conventional medicines. The beauty of gene editing, he said, is that “you could theoretically design a very personalized therapy for every patient or every infection“, since no two people have exactly the same kind of bacteria, and drugs affect everyone differently. A customized therapy for each individual is also conceivable, “because we can build these things very quickly in a day or two in the lab“. But that day is far off, he said, blocked by layers of regulation. “We’re kind of going back to that old concept of the silver bullet, but we’re now entering an era where the ability to read and write DNA gives us the ability to make silver bullets at a much more rapid pace and with much more targeting ability, “ he said. They have done initial testing in larvae of moths, but obviously, he said, “we want to push this toward human use, so we’re now working on larger animal experiments, like mice, and if we’re successful we’re hoping to use the technology in clinical and preclinical trials“. Superbugs beware.

Justin was always prepared. His motto was “Never throw anything out, you never know when it might come in handy.“ His bedroom was so full of flat bicycle tires, bent tennis rackets, deflated basketballs, and games with missing pieces that you could barely get in the door. His parents pleaded with him to clean out his room. “What use is a fish tank with a hole in the bottom?“ his father asked. But Justin simply smiled and repeated his motto, “Never throw anything out, you never know when it might come in handy.“ When Justin was away from home, he always carried his blue backpack. He liked to think of it as a smaller version of his bedroom — a place to store the many objects that he collected. It was so worn and stretched that it hardly resembled a backpack anymore. It was full of the kind of things that seemed unimportant, but when used with a little imagination, might come in handy. Justin had earned a reputation for figuring things out and getting people out of otherwise hopeless situations. Many of his classmates and neighbours sought him out when they needed help with a problem. On the first day of school, his friend Kenny, came looking for Justin. “Do you think you have something in your bag that could help me remember my locker combination?“ he asked. “I lost the scrap of paper it was written on. I have science class in two minutes and if I’m late on the first day, it’ll make me look bad for the rest of the year.“ Kenny looked genuinely worried. “Relax, “ Justin said, taking his backpack off and unzipping the top. “Remember how you borrowed my notebook in homeroom to write the combination down? Well, I know how we can recover what you wrote.“ He took the notebook and a soft lead pencil out of his bag. The page that Kenny had written on had left faint indentations on another page in the notebook. Justin held the pencil on its side and rubbed it lightly over the indentations. Slowly but surely the numbers of the locker combination appeared in white, set off by the gray pencil rubbings. “That’s amazing!“ Kenny said. “I owe you one.“ And he dashed off to open his locker. During science class, Mr. Tran was lecturing on the structure of the solar system using a model. He made a sudden gesture and the model fell apart. Planets and rings and connector rods went everywhere, rolling and clattering and disappearing under desks. The students scrambled around on the floor for ten minutes and were finally able to recover every piece except one — a connector rod that was lodged in a crack between two lab stations. “If we had a magnet, “ said Mr. Tran, “we could easily coax it out that way. But I loaned all of the magnet kits to the elementary school yesterday.“ Justin was already searching through his backpack. “I have some materials that will work just as well, I think, “ he told Mr. Tran. He pulled out a battery, an iron nail, and some electrical wire and tape, while Mr. Tran and the other students looked on in amazement. “Why do you have all of that stuff?“ Louise Baxter asked. Justin just smiled and repeated his motto, “Never throw anything out, you never know when it might come in handy.“ By wrapping the wire around the nail and taping each end to a battery terminal, he was able to make a magnet strong enough to lift the rod out of the crack. “Bravo!“ said Mr. Tran. “No problem, “ said Justin. After school, Justin rode the bus to the mall where he worked at a music store. His boss, Gail, was taking inventory of all of the CDs and tapes in the classical music section. As he helped a customer at the register, Justin heard her exclaim, “Oh, no! I forgot my glasses! There’s no way I can read this list without them.“ Justin sighed, picked up his backpack, and walked over to Gail. “I think I can help you out, “ he said, unzipping the bag. While Gail watched in surprise, he pulled out a jar of petroleum jelly, a washer, a glass slide, and a small bottle of water. He put the jelly on the bottom of the washer, placed it securely, jelly-side down, on the glass slide, and then put a drop of water in the center of the washer. He put the contraption on top of the inventory list and said to his boss, “See what happens when you look through the water droplet.“ Gail looked and her eyes widened with delight. “Wow!“ she cried. “It enlarges the print that I’m looking at, just like a magnifying glass!“ She patted Justin on the back. “I’m all set now, “ she said. “Thanks.“ Justin smiled. “No problem, “ he said, returning to the register. It was just another day in the life of the boy whose motto was “Never throw anything out, you never know when it might come in handy.“

PASSAGE TWO

In stormy times, investors look for something solid to hang onto — something like gold. The World Bank president himself, Robert Zoellick, suggested in November that the world’s economies could use the old reliable metal to help stabilize their currencies. For these and many other reasons, professional gold-fund manager Shayne McGuire argues that gold has nowhere to go but up. The following essay is adapted from McGuire’s latest book, Hard Money: Taking Gold to a Higher Investment Level. Gold used to be regarded as an investment for losers — for the crazies forever expecting the financial apocalypse. To the great economist John Maynard Keynes, it was a “barbarous relic“ of a primeval economic past. Many people have abandoned that lousy stereotype, now that the debt-driven bubbles in stocks and real estate have burst. Following the collapse of the world’s largest bank, the Royal Bank of Scotland, and the largest insurer, the American Insurance Group, among many other notable institutions now owned and directed by Western governments, people have come to understand the need for time-proven financial insurance that can insulate their wealth from government and financial firms. And there’s only one viable and liquid investment that enables a person to pull his or her wealth out of the financial system: gold. Buying gold has been the best method for shorting the government. Betting against government — that is, on a sudden, sharp rise in inflation — has strong odds in the midst of surging government deficits. Hyperinflation is fortunately a rare event, and it is unlikely to emerge at present. But consider that all 30 documented cases of hyperinflation — that is, a situation where prices rise by at least 50 percent per month — have been caused by deficits that got out of control. Hyperinflation invariably emerges in a deflationary environment of weak economic activity, such as the one that now threatens the United States, European nations, and Japan. It can erupt when the public grows wary of the money being printed in growing quantities by monetary authorities, which are forced to buy — to “monetize, “ in the financial vernacular—a surging supply of government bonds that the markets no longer all want to buy. Every currency in history has eventually fallen against gold — most dramatically in times like these, times of surging liabilities and an increasing inability to meet them. Gold is the only credible currency whose quantity cannot be expanded at will to meet the spending needs of governments in distress. By its very nature it remains scarce and rises in value as the supply of paper money grows. And I think it’s safe to say that following the most dramatic credit crisis since the Great Depression — one that is continuing to produce ripple effects, like events in Greece that are broadening into Europe itself — we are likely to see historic investment shifts that will provide great opportunities. One major beneficiary will be gold. I strongly believe that present financial conditions are about to transform the investment strategies of the world’s largest investment funds in a way that will cause gold to surge substantially higher. To understand why, consider present asset allocation at some of the world’s largest investment funds. Pension funds, like the one I work for, have a significant effect on the world’s markets, since they collectively manage $24 trillion. But gold plays a negligible role in their asset allocations. Teacher Retirement System of Texas, whose GBI Gold Fund I manage, probably holds a larger percentage of assets in gold than any other large ($10 billion and higher) pension fund in the world, but our holdings in the precious metal are modest in comparison with any major type of asset like stocks and bonds. And so it is with other pension funds. Since commodities typically represent around 3 percent of a typical fund’s total assets, and the precious metal makes up less than 5 percent of commodity allocation, that makes gold only 0.15 percent of a fund’s total assets. Add in the value of gold-mining stocks and precious-metals exchange-traded funds (maybe another 0.15 percent of total assets, at most), and a typical pension fund holds less than a third of 1 percent in gold — that is to say, virtually nothing.

PASSAGE THREE

PASSAGE FOUR

1925年2月24日，国父孙中山病危时，留下一段《家事遗嘱》： “余因尽瘁国事，不治家产。其所遗之书籍、衣物、住宅等均付吾妻宋庆龄，以为纪念。余之儿女已长成能自立，望各自爱，以继余志。此嘱。” 中山先生艰苦奋斗40年，功勋卓然。但终身廉洁，从未为自己和子女亲属置办过田地遗产。他任过国家临时大总统，官可谓高矣，然而从不追求俸禄。临终留下的遗物只有生前的一些衣物，2000多本书籍杂志，还有一所旅居加拿大的华侨为他募捐的住宅。

(S)=Mrs. Smith (I)=Interviewer (I): Good teachers can always find a way to encourage their students to work hard and learn well. That year, in the local school, there was a math teacher who became well known nationwide for her webpage stories. Today we have with us Irene Smith. She has worked with her students for more than ten years to research, write and illustrate those stories. Irene, tell me, how does a multimedia and math teacher end up leading a project that has students write stories about local history? (S): My lab is the high school’s multimedia lab. When developing my program, the district decided that they would like to have one room—my room—house all new technologies. So ten years ago, I received several scanners that, at the time, cost about $1, 100, and I wanted to have a project that put them to good use. I asked my students to look for really old pictures that maybe their grandparents or their parents had in their possession. The first pictures that a student brought in were in a box of maybe 80 photographs that her grandmother had in her attic. Some of the photos were over a hundred years old! There were photographs of football players, sports activities, old buildings—just wonderful pictures. The kids loved seeing grandma in a bathing suit! So, that’s how the project started. We started scanning the photos and we built ourselves a database. The second year we did the same thing: we brought in more photos, and we continued to scan. (I): So, how did the story writing component come about? (S): I’m an advocate of reading, having four of my own children. When they were younger I read to them all the time, and today they are all strong readers. I thought, wouldn’t it be neat if one of the English teachers could have her students write stories that my students could associate with our old pictures. We could then build these stories into webpages and post them on the Internet. Our third graders have local history in their curriculum so I thought that we could gear the project to them. (I): I would imagine that this project would be a great way for an English teacher to pursue various teaching goals and standards. (S): In our school district, we have major assignments for each course called benchmarks. One of our English teacher’s benchmarks was a writing and research project. Thanks to Mrs. Happeny and her benchmark, we had about 100 students writing our stories that first year. Over the years, we have had so much success with this project that 1 think that we are going to do it again this school year. This is the end of Part One of the interview. Questions 1 to 5 are based on what you have just heard. Question One How did the teacher become famous? Question Two What was Irene’s project mainly about? Question Three What did they do in the first year when the project started? Question Four Why did Irene combine her project with reading and writing? Question Five What does benchmark mean in her school? She was good at encouraging her students. She had developed some good webpage stories. She had a project researching local history. She had taught math, computer science and English writing.

If only the same could be said of electric bills. The price of U.S. solar power has dropped a whopping 70 percent since 2009, even as panels get smarter. The figure, cited in a report this week from Lawrence Berkeley National Laboratory, coincides with SolarCity’s debut on Friday of what it calls the world’s most efficient rooftop solar panel. The largest residential solar installer in the U.S. says its module can produce 38 percent more power than a standard one, yet costs less to produce power. Not bad for an industry that had no large-scale U.S. presence just a decade ago. Photovoltaic panels currently contribute only about 1 percent of all electricity, but lower costs are helping fuel the expansion of large, utility-size projects. As historic UN climate talks near, solar’s latest strides are key in the worldwide race to slash carbon emissions by paring back dependence on fossil fuels. “It is quite remarkable and exciting when you have this amount of growth, and an industry goes from basically being a hobby to a mainstream industry, “ says Peter Rive, SolarCity’s co-founder and chief technology officer. (Rive’s cousin and SolarCity’s chairman, Elon Musk, is also seeking to boost solar’s appeal to utilities with his recently launched Tesla battery system.) The company’s new panel “takes solar a step further to be a cheaper energy source without requiring federal incentives such as the investment tax credit, “ Rive says. That credit currently returns 30 percent of a solar system’s cost to the buyer. Its looming expiration at the end of next year has lent urgency to the industry’s efforts to bring down prices. The Berkeley Lab report predicts a “frenzied pace of construction over the next 15 months“. Contracts to buy power from large-scale solar projects average 5 cents per kilowatt hour, according to the report, while electricity prices on the wholesale market run from 3 cents to 6 cents per kilowatt hour. The plunging cost of solar hasn’t translated to lower electric bills so far: in most regions — even ones with big solar plants — people are paying a bit more for power than they did a few years ago, because many different factors go into determining retail electricity rates. Rather, the trend means more of that power might be coming from carbon-free sources that are less subject to the price shocks of fossil fuels. “While it’s difficult to make a direct cost comparison between new solar projects and existing fossil fuel power plants, “ says report co-author Mark Bolinger, “Solar is getting to a point where it can compete with coal and natural gas for electricity in some places.“ “Just a few years ago, that was much more of a stretch, “ he says. The falling price of power from large-scale solar projects reflects the lower cost of building them. The report notes that cost fell by more than 50 percent between 2009 and 2014. At the same time, solar farms have seen a “notable improvement“ in how much power they put out, thanks to smarter siting and better technology. SolarCity is aiming to apply its own gains in efficiency and cost to the residential market when it begins production at its 1-gigawatt facility in Buffalo, New York, in early 2017. Its new rooftop panel, which earned a rating of 22.04 percent efficiency in a third-party certification test, surpasses an earlier record set by SunPower, which has a high-efficiency model rated at 21.5 percent. Another trend Bolinger called “encouraging“: Solar’s reach is expanding. Most development has been centered in the Southwest, but Bolinger says big solar power contracts are cropping up in Alabama, Arkansas, Florida, and Georgia — states that “haven’t seen much solar development in the past to speak of. Of course, prices won’t keep tumbling so steeply in the years ahead. What we might see instead, Bolinger says, is that the market for solar will just continue to expand.

PASSAGE ONE

Children today spend more time stare at computer 【S1】______ and TV screens both at school and at home. Scientific 【S2】______ studies show an epidemic of myopia (also known as nearsightedness) has struck children—and it is spreading faster in many countries. Doctors warn that sitting too close to a computer, especially fixes your eyes at a computer or 【S3】______ TV screen from close range, increases the risk of myopia. The cause of myopia is difficult to explain in simple terms. While some say sitting near computers and TV screens is one of the reasons, others say children born to nearsighted parent/parents are vulnerable. 【S4】______ Can genes or the environment, or a combination of two 【S5】______ explain the growing prevalence of myopia across many countries? How can parents understand what causes myopia and the risks it poses to their children’s eyesight? Children suffering from myopia have trouble seeing close objects clearly. The eyeball is thought to become 【S6】______ longer, because of which less effort is needed to see up close. Moreover, the elongated eye can no longer focus on 【S7】______ distant objects. Symptoms of myopia are rarely noticed in early 【S8】______ childhood. Myopic children must hold books very close 【S9】______ to their face or may not be able to read the writing on the blackboard in school. They may squint and complain of head and eyestrain. 【S10】______

You can find a table below showing the population change from 2010 to 2015, projected by the Population Council in New York, and a short material explaining some conditions of population prediction. Read them carefully and write an essay of no less than 300 words, in which you should: 1. summarize the ideas in both materials; 2. comment on the situation. Table [*] Excerpt ASSUMPTIONS UNDERLYING THE PROJECTIONS (http://info.worldbank.org/etools/docs/library/48424/mls3bongaarts.pdf) The population of the world now increases every year because the global birth rate exceeds the death rate. The annual birth and death rates of populations are in turn primarily determined by levels of fertility and mortality experienced by individuals. The most widely used fertility indicator is the total fertility rate (TFR). Mortality is usually measured by the life expectancy at birth (LE), which equals the average number of years a newborn would live if subjected to a given set of age-specific mortality rates. In order to make longrange population projections, assumptions have to be made about the future trajectories of fertility and mortality. … Future trends in fertility in the South are based on the assumption that the total fertility rate will eventually reach and then remain at the so-called “replacement“ level in all regions. Replacement fertility is just above 2 bpw and it represents the level at which each generation just replaces the previous one, thus leading to zero population growth. Below-replacement fertility produces, in the long run, population decline. … Mortality levels have also changed rapidly over the past few decades. By the early 1990s, Latin America had reached mortality levels similar to those prevailing in the North in the 1950s, and Asia was not far behind. Africa has had the highest mortality levels and the slowest rate of improvement. By 2025, mortality conditions in Asia and Latin America are expected to be similar to those that prevailed in the North in the 1970s. Africa will continue to lag, in part because the continent is most heavily affected by the AIDS epidemic. It should be noted that the assumptions made by the UN about future trends in fertility and mortality are not based on a firm theoretical basis. Instead, the UN relies on empirical regularities in past trends in the now-developed countries, mostly in the North, where fertility declined to around the replacement level, and increases in life expectancy became smaller over time. This is a plausible approach that unfortunately leaves room for potential inaccuracies in projection results.

The following statements are the reasons for the dropping of the solar power price in the U.S. EXCEPT______.

What can we learn about “the investment tax credit“ in the passage ?

According to the passage, which of the following statements is TRUE?

A suitable title for the passage would be______.