What are the fire triangle that the firefighters refer to?There are three conditions that need to be present in order for a wildfire to burn, which firefighters refer to as the fire triangle: fuel, oxygen, and a heat source. Fuel is any flammable material surrounding a fire, including trees, grasses, brush, even homes. The greater an area’s fuel load, the more intense the fire. Air supplies the oxygen a fire needs to burn. Heat sources help spark the wildfire and bring fuel to temperatures hot enough to ignite. Lightning, burning campfires or cigarettes, hot winds, and even the sun can all provide sufficient heat to spark a wildfire. Although four out of five wildfires are started by people, nature is usually more than happy to help fan the flames. Dry weather and drought convert green vegetation into bone-dry, flammable fuel; strong winds spread fire quickly over land; and warm temperatures encourage combustion. When these factors come together all that’s needed is a spark—in the form of lightning, arson, a downed power line, or a burning campfire or cigarette—to ignite a blaze that could last for weeks and consume tens of thousands of acres. These violent infernos occur around the world and in most of the 50 states, but they are most common in the U. S. West, where heat, drought, and frequent thunderstorms create perfect wildfire conditions. Montana, Idaho, Wyoming, Washington, Colorado, Oregon, and California experience some of the worst conflagrations in the U. S. In California wildfires are often made worse by the hot, dry Santa Ana winds, which can carry a spark for miles. Firefighters fight wildfires by depriving them of one or more of the fire triangle fundamentals. Traditional methods include water dousing and spraying fire retardants to extinguish existing fires. Clearing vegetation to create firebreaks starves a fire of fuel and can help slow or contain it. Firefighters also fight wildfires by deliberately starting fires in a process called controlled burning. These prescribed fires remove undergrowth, brush, and ground litter from a forest, depriving a wildfire of fuel. Wood, bushes and dry grass. A heat source, carbon dioxide and fuel. Oxygen, fuel and a heat source. Forest, grassland and a heat source.

All thermal radiation from a planetary surface absorbed by atmospheric greenhouse gases is re-radiated directly back toward the planet.The greenhouse effect is a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions. Since part of this re-radiation is back towards the surface and the lower atmosphere, it results in an elevation of the average surface temperature above what it would be in the absence of the gases. Solar radiation at the frequencies of visible light largely passes through the atmosphere to warm the planetary surface, which then emits this energy at the lower frequencies of infrared thermal radiation. Infrared radiation is absorbed by greenhouse gases, which in turn re-radiate much of the energy to the surface and lower atmosphere. The mechanism is named after the effect of solar radiation passing through glass and warming a greenhouse, but the way it retains heat is fundamentally different as a greenhouse works by reducing airflow, isolating the warm air inside the structure so that heat is not lost by convection. If an ideal thermally conductive blackbody were the same distance from the Sun as the Earth is, it would have a temperature of about 5. 3 degrees Celsius. However, since the Earth reflects about 30% of the incoming sunlight, this idealized planet’s effective temperature (the temperature of a blackbody that would emit the same amount of radiation)would be about — 18 degrees Celsius. The surface temperature of this hypothetical planet is 33 degrees Celsius below Earth’s actual surface temperature of approximately 14 degrees Celsius. The mechanism that produces this difference between the actual surface temperature and the effective temperature is due to the atmosphere and is known as the greenhouse effect. Earth’s natural greenhouse effect makes life as we know it possible. However, human activities, primarily the burning of fossil fuels and clearing of forests, have intensified the natural greenhouse effect, causing global warming. 1. All thermal radiation from a planetary surface absorbed by atmospheric greenhouse gases is reradiated directly back toward the planet. 2. Re-radiation results in an elevation of the average surface temperature above what it would be without the gases. 3. Scarcely can solar radiation at the frequencies of visible light passes through the atmosphere. 4. Greenhouse gases can re-radiate much of the energy of infrared radiation to the surface and lower atmosphere. 5. The mechanism and the way it retains heat is of the same with that of the greenhouse. 6. If an ideal thermally conductive blackbody were the same distance from the Sun as the Earth is, it would have a temperature of about 15. 3 degrees Celsius. 7. About 30% of the incoming sunlight can be reflected by the Earth. 8. The greenhouse effect and some other factors produce the difference between the actual surface temperature and the effective temperature. 9. Earth’s natural greenhouse effect makes life impossible. 10. The burning of fossil fuels and clearing of forests have intensified the natural greenhouse effect. 正确错误

What’s American public’s view towards gun control?The American public is evenly divided over whether the country even needs gun control. According to the Pew Research Center, which for 20 years has tracked American attitudes toward gun ownership, 47% now say it is more important to control gun ownership, while 46% say it is more important to protect the rights of Americans to own guns. Next you may be wondering why in the heck Americans so cherish their guns. Gun ownership in America has a sacred legacy dating back 200 years to the days of the Wild West. According to romanticized national mythology, “ real men“ were tough guys who wielded their guns to protect their women and children from the marauding Indians. The reality, of course, was that the Americans used their guns to murder and rob the Native Americans and drive them from the land. But those inconvenient truths are glossed over in favor of the story of guns as the potent symbol and protector of “us,“ the Americans, the good-guys. It’s that proud self-image of male courage and self-reliance that still drives American gun culture today. But to today’s gun enthusiasts, Native Americans are no longer a threat. The new bad-guys are the government. Today when gun enthusiasts talk about “freedom“ , they’re talking about one particular kind of freedom — freedom from government oppression. To them, unrestricted access to guns is what protects individuals from the tyranny of government. And the only way to ensure freedom is to ensure that individuals can confront the government through their weapons. As National Rifle Association CEO Wayne LaPierre says in his book Guns, Crimes and Freedom: The people have the right, must have the right, to take whatever measures necessary, including force, to abolish oppressive government. Most Americans are in favor of gun ownership. Most Americans are in favor of gun control. The American public is evenly divided over the issue of gun control. The American public is indifferent to the issue of gun control.

What does the speaker think of Toronto?Toronto is a beautiful city but it’s not for me! It is his favorite. It is not suitable for him. He likes it because it’s beautiful. He dislikes its beauty.

Rock climbing is an activity in which participants climb up, down or across natural rock formations or artificial rock walls. The goal is to 【L1】______of a formation or the end point of a usually 【L2】______route without falling. To successfully complete a climb, one must【L3】______of the route safely. Due to the length and 【L4】______required, accidents are more likely to happen on 【L5】______than ascent, especially on the larger 【L6】______pitches (class III-IV and /or multi-day grades IV-VI climbs). Rock climbing 【L7】______have the objectives of either completing the route in 【L8】______or attaining 【L9】______point on an increasingly difficult route. 【L10】______, another activity involving the scaling of hills and similar formations, is 【L11】______rock climbing. However, rock climbing is generally【L12】______by its sustained use of hands to support the climber’s weight as well as 【L13】______. Rock climbing is a 【L14】______ demanding sport, one that often tests a climber’s strength, endurance, 【L15】______and balance along with mental control. It can be a【L16】______and knowledge of proper climbing techniques and usage of 【L17】______climbing equipment is crucial for the safe completion of routes. Because of the 【L18】______of rock formations around the world, rock climbing has been 【L19】______several different styles and 【L20】______.Rock climbing is an activity in which participants climb up, down or across natural rock formations or artificial rock walls. The goal is to reach the summit of a formation or the end point of a usually predefined route without falling. To successfully complete a climb, one must return to the base of the route safely. Due to the length and extended endurance required, accidents are more likely to happen on descent than ascent, especially on the larger multiple pitches (class III-IV and /or multi-day grades IV-VI climbs). Rock climbing competitions have the objectives of either completing the route in the quickest possible time or attaining the farthest point on an increasingly difficult route. Scrambling, another activity involving the scaling of hills and similar formations, is similar to rock climbing. However, rock climbing is generally differentiated by its sustained use of hands to support the climber’s weight as well as to provide balance. Rock climbing is a physically and mentally demanding sport, one that often tests a climber’s strength, endurance, agility and balance along with mental control. It can be a dangerous activity and knowledge of proper climbing techniques and usage of specialized climbing equipment is crucial for the safe completion of routes. Because of the wide range and variety of rock formations around the world, rock climbing has been separated into several different styles and sub-disciplines.

On which day is the hotel available?I’m sorry. The hotel for Monday, Wednesday, Friday and weekend is booked up. Saturday. Tuesday. Monday. Friday.

Who was the big winner at the 57th annual Grammy?Soulful singer Sam Smith was the big winner Sunday night at the 57 th annual Grammy Awards in Los Angeles, California. Smith took home four awards: Best New Artist, Best Pop Vocal Album, Song of the Year and Record of the Year. The British artist’s 2014 album, “In the Lonely Hour,“ was about the painful break-up he experienced last year with someone he loved. But Smith noted the happy ending. He accepted his final award for Record of the Year by thanking the one who broke his heart. The big surprise of the night was in the Album of the Year category. Many expected Beyonce to win for her self-titled album. But musician Beck took home the award for his album “ Morning Phase.“ The recording was also honored with the Best Rock Album award. Kanye West played a little trick on Beck and the crowd at the Staples Center. He jumped up on stage as Beck was accepting the award. The move was similar to the bad behavior he displayed at the 2009 Video Music Awards. At that event, West interrupted Taylor Swift’s acceptance speech to tell the crowd that Beyonce deserved the award that Swift had just received. However, Sunday night, West left the stage immediately, laughing. The audience realized it was just a prank. West even fooled Beyonce’s husband. Beyonce did not go home with empty hands Sunday night. She won three Grammys, including Best R&B Song and Best R&B Performance for her song, “Drunk in Love. “ Other Grammy winners included country singer Miranda Lambert and rapper-singer Pharell Williams. The show included a video message from President Barack Obama about ending domestic violence. Critical opinion was mixed about the musical performances at the Grammy Awards. Most critics praised Lady Gaga and Tony Bennett for their delivery of “Cheek to Cheek. “ And the crowd roared for the performance of Sia’s song, “Chandelier. “ Actresses Kristen Wiig and Maddie Ziegler danced to the song. Beyonce. Kanye West. Sam Smith. Beck.

MOOCs going global, giving access: miracle or myth? The event saw MOOC providers FutureLearn and Coursera going head to head with skeptics who believe that MOOCs will ultimately prove damaging to education in the developing world. The MOOC providers spoke about the benefits of high quality, free education being made available to millions of people who otherwise would lack the physical and financial means to attend universities. The skeptics thought that there needed to be a conversation on how “ to use innovation in a way that supports the global academy of commons rather than simply advancing the individual aspirations of institutions“. The Future of MOOCs Simon Nelson informed the conference that “ Some see MOOCs as the biggest thing to solve world poverty; others dismiss them as a fad that will have disappeared in two years. Neither is true. MOOCs are not miracles and they are certainly not myths,“ According to Nelson all MOOCs are doing is offering “ access to institutions that previously were only open to those people who could physically walk through the door,“ He believes that rather than viewing MOOCs as a threat MOOCs should be seen as offering academics tools to promote their teaching. He stressed that while he saw this as “an overwhelming positive“, we should “not assume it is a panacea for problems in the developing world. “ Why have MOOCs proved so successful? What is it about MOOCs that has captured the imagination of today’s students and led to their being so successful? According to Daphne Koller this can be summed up in two main reasons. i . A greater understanding of the power of the visual. It is now possible to teach very large numbers of students with only a single lecturer. This makes the cost per student tiny. ii. A growing willingness on the part of students to engage in social interaction online. This allows peer-to-peer learning and teaching. This is a radically different approach from the traditional hub-and-spoke method which involves a single infrastructure and at least several dozen lecturers teaching. The new approach allows much greater scalability and this is key to the MOOC teaching method. Where do MOOCs draw their students from? According to Daphne Koller there are several distinct categories of students participating in MOOCs. i . Those who attend regular universities that employ MOOCs to enhance the learning experience. This is the smallest group of MOOC students. ii. Those who have completed higher education many years ago, studying subjects which are now obsolete or no longer relevant to their careers. Most of these people are not in a position to return to full-time university study. MOOCs offer an opportunity to enjoy lifelong learning. iii. Around one third of Coursera’s learners are located in the developing world. Koller stressed the potential for MOOCs to enhance capacity for higher education in places like India. Koller did admit that there are challenges facing MOOCs, one of which is the lack of MOOC content for people in their own languages. She also mentioned the establishment of learning hubs. Learning hubs are locations scattered around the world where students can take MOOCs while participating in study groups and benefiting from some supervision. A divided world Despite the positive atmosphere surrounding MOOCs a note of caution was sounded by several professors. First, Apoorvanand Jha, from the University of Delhi spoke about the impact of MOOCs in relation to cases like Malala Yousafzal in Pakistan. He said that there was a view that MOOCs would allow them to study at home and therefore protect them from assault or attack. He argued that this view “ ignores the transformative role of education itself. For the vast majority of the world, knowledge and education is about making a claim for a share of cultural capital. “ The vice-chancellor at the University of Witwatersrand, Johannesburg, Professor Adam Habib admitted that the arrival of MOOCs would mean big changes in higher education. Cynicism could prevent innovation, and romanticism could raise unrealistic expectations. “We need nuance. “ He went on to raise three areas of particular concern. i . The quality of education provided by MOOCs. ii. The dangers of US and European education being perceived as better by students in the developing world and the negative impact this could have on universities in the developing world if student prefer to become accredited by western universities. ill. The financial model employed by MOOCs. Professor Koller responded to the financial concern by stating that Coursera intended that their MOOCs would always remain free with the costs being met by premium services, including credentialing. He argued that universities in both the developing and the developed world should not be competing but working together. He said that universities should be engaging in building cross border partnerships and thinking about “how to enable a global academy of commons. “

Which of the following might be heat sources to spark a wildfire?

According to the passage, which does NOT tell us the reason why nature often helps fan the flames?

Why are wildfires in California usually made worse by Santa Ana winds?

What makes it feasible for firefighters to fight wildfire?