-
They have given up the hope to save their friend from drowning. ended abandoned built strengthen
-
I seldom watch TV. rarely frequently normally occasionally
-
The dentist has decided to take out the girl’s bad tooth. dig draw pull extract
-
These are their motives for doing it. reasons excuses answers plans
-
The river widens considerably as it begins to turn west. twists stretches broadens bends
-
Henry cannot resist the lure of drugs. abuse flavor temptation consumption
-
A great deal has been done to remedy the situation. maintain improve assess protect
-
You look smart in the new suit. clever handsome loyal brave
-
He hasn’t the funds to carry out his design. make keep change implement
-
I was astonished at the news of his escape. amused amounted amazed approached
-
It’s almost 5 o’clock, time to quit. increase stop continue keep
-
Relief workers were shocked by what they saw. moved touched surprised worried
-
The weather is a constant subject of conversation in Britain. question problem title topic
-
This is not typical of English, but is a feature of the Chinese language. particular characteristic remarkable idiomatic
-
It is virtually impossible to persuade him to apply for the job. simply almost totally completely
-
Computer Virus
The computer virus is an outcome of the computer overgrowth in the 1980s. The cause of the term “computer virus“ is the likeness between the biological virus and the evil program infected with computers. The origin of this term came from an American science fiction“The Adolescence of P—l“writ-ten by Thomas J . Ryan, published in 1977. Human viruses invade a living cell and turn it into a factory for manufacturing viruses. However, computer viruses are small programs. They replicate by attaching a copy of themselves to another program.
Once attached to host Program, the viruses then look for other programs to “infect“. In this way, the virus can spread quickly throughout a hard disk or an entire organization when it infects a LAN or a multi—user system. At some point, determined by how the virus was programmed the virus attacks. The timing of the attack can be linked to a number of situations, including a certain time or date, the presence of a particular file, the security privilege level of the user, and the number of times a file is used. Likewise, the mode of attack varies. So —called “benign“ viruses might simply display a message, like the one that infected IBM’s main computer system last Christmas with a season’s greeting.
Malignant viruses are designed to damage the system. The attack is to wipe out data, to delete flies or to format the hard disk.
What Kind of Viruses Are There? There are four main types of viruses: shell, intrusive, operating system and source ode. Shell viruses wrap themselves around a host program and don’t modify the original program. Shell programs are easy to write, which is why about half of viruses are of this type. Intrusive viruses Invade an existing program and actually insert a portion of themselves into the host program. Intrusive viruses are hard to write and very difficult to remove without damaging the host file.
-
English and English Community
1. There is no doubt that English is a useful language. The people who speak English today make up the largest speech community in the world with the exception of speakers of Chinese.
2. A speech community is similar to other kinds of communities. The people who make up the community share a common language. Often they live side by side, as they do in a neighborhood(街坊), a village, or a city. More often they form a whole country. National boundaries, however, are not always the same as the boundaries of a speech community. A speech community is any group of people who speak the same language no matter where they happen to live.
3. We may say that anyone who speaks English belongs to the English speech community. For convenience(方便), we may divide the speakers into two groups;one in which the speakers use English as their native language, the other in which the speakers learn English as a second language for the purpose of education, commerce, and so on.
4. Learning a second language extends one’s vision and expands the mind. The history and literature of a second language record the real and fictional(虚构的)lives of people and their culture; a knowledge of them adds to our ability to understand and to feel as they feel. Learning English as a second language provides another means of communication through which the window of the entire English speech community becomes a part of our heritage.
A. Threat Posed by English
B. Definition of a Speech Community
C. Benefits of Learning a Second Language
D. Advantages of Learning Chinese
E. Two Groups of the English Speech Community
F. A Widely Used Language
-
A. a second language
B. the same language
C. the same speech community
D. any other language
E. national boundaries
F. a part of one’s heritage
-
A Gay Biologist
Molecular biologist Dean Hamer has blue eyes, light brown hair and a good sense of humor. He smokes cigarettes, spends long hours in an old laboratory at the US National Institute of Health, and in his free time climbs up cliffs and points his skis down steep slopes. He also happens to be openly, matter of factly gay.
What is it that makes Hamer who he is? What, for that matter, accounts for the talents and traits that make up anyone’s personality? Hamer is not content merely to ask such questions; he is trying to answer them as well. A pioneer in the field of molecular psychology, Hamer is exploring the role genes play in governing the very core of our individuality. To a remarkable extent, his work on what might be called the gay, thrill-seeking and quit-smoking genes reflects how own genetic predispositions.
That work, which has appeared mostly in scientific journals, has been gathered into an accessible and quite readable form in Hamer’s creative new book, Living with Our Genes. “You have about as much choice in some aspect of your personality. “ Hamer and co-author Peter Copeland write in the introductory chapter, “as you do in the shape of your nose or the size of your feet. “
Until recently, research into behavioral genetics was dominated by psychiatrists and psychologists, who based their most compelling conclusions about the importance of genes on studies of identical twins. For example, psychologist Michael Bailey of Northwestern University famously demonstrated that if one identical twin is gay, there is about a 50% likelihood that the other will be too. Seven years ago, Hamer picked up where the twin studies left off, homing in on specific strips of DNA that appear to influence everything from mood to sexual orientation.
Hamer switched to behavioral genetics from basic research, after receiving his doctorate from Harvard, he spent more than a decade studying the biochemistry of a protein that cells use to metabolize heavy metals like copper and zinc. As he was about to turn 40, however, Hamer suddenly realized he had learned as much about the protein as he cared to. “Frankly, 1 was bored, “ he remembers, “and ready for something new. “
Homosexual behavior, in particular, seemed ripe for exploration because few scientists had dared tackle such an emotionally and politically charged subject. “I’m gay, “ Hamer says with a shrug, “but that was not a major motivation. It was more of a question of intellectual curiosity—and the fact that no one else was doing this sort of research. “
-
DNA Fingerprinting
DNA is the genetic material found within the cell nuclei of all living things. In mammals the strands of DNA are grouped into structures called chromosomes. With the exception of identical siblings(as in identical twins), the complete DNA of each individual is unique.
DNA fingerprinting is sometimes called DNA typing. It is a method of identification that compares bits of DNA. A DNA fingerprint is constructed by first drawing out a DNA sample from body tissue or fluid such as hair, blood, or saliva. The sample is then segmented using enzymes, and the segments are arranged by size. The segments are marked with probes and exposed on X-ray film, where they form a pattern of black bars—the DNA fingerprint. If the DNA fingerprints produced from two different samples match, the two samples probably came from the same person.
DNA fingerprinting was first developed as all identification technique in 1985. Originally used to detect the presence of genetic diseases, it soon came to be used in criminal investigations and legal affairs. The first criminal conviction based on DNA evidence in the United States occurred in 1988. In criminal investigations, DNA fingerprints derived from evidence collected at the crime scene are compared to the DNA fingerprints of suspects. Generally, courts have accepted the reliability of DNA testing and admitted DNA test results into evidence. However, DNA fingerprinting is controversial in a number of areas:the accuracy of the results, the cost of testing, and the possible misuse of the technique.
The accuracy of DNA fingerprinting has been challenged for several reasons. First, because DNA segments rather than complete DNA strands are “fingerprinted“: a DNA fingerprint may not be unique; large-scale research to confirm the uniqueness of DNA fingerprinting test results has not been conducted. In addition, DNA fingerprinting is often done in private laboratories that may not follow uniform testing standards and quality controls. Also, since human beings must interpret the test, human error could lead to false results.
DNA fingerprinting is expensive. Suspects who are unable to provide their own DNA to experts may not be able to successfully defend themselves against charges based on DNA evidence.
Widespread use of DNA testing for identification purposes may lead to the establishment of a DNA fingerprint database.
