单选题What does the word "concurrent" (Par

单选题Despite years of searching, scientists have detected no signs of life {{U}}beyond {{/U}} our own solar system.

单选题The courses aim to give graduates an up-to-date grasp of their subject and ______ laboratory skirls.

单选题Jennifer Senior suggests in her article that raising a child can bring ______.

单选题Wilmut maintains that cloning animals has tremendous potential for helping people. Cloned Sheep, he says, could be used as living drug factories. Scientists could "engineer" sheep that produce drugs in their milk. And by altering the proteins on the surfaces of animal organs to make them more like human organs, scientists believe they may be able to create a plentiful source of organ donors for people. Why not clone humans as organ donors? Theoretically, Wilmut says, there is no reason his techniques couldn't someday be used to clone people. Think about the possibilities: a whole basketball team of Michael Jordans, a scientific panel of Albert Einsteins, a movie starring and co-starring Brad Pitts. On a more serious note, some experts argue that couples who have difficulty having a baby could make copies of themselves. And parents whose child has a fatal disease like cancer might be able to clone the child, creating a twin who could be a bone-marrow (骨髓) donor. But even Ian Wilmut draws the line at cloning humans. "All of us would find that offensive," he says. Several countries, including Britain, Denmark, Germany and Australia, have made all scientific work on cloning humans illegal. The U.S. has no such law, but President Clinton has set up a panel of scientists and philosophers to study the issue. In the meantime, Clinton has imposed a ban on using federal money to clone humans. Humans are more than the sum of their genes, argues a philosopher at one research institute. Though they look exactly the same, clones are not necessarily exact copies. The younger twin might grow up with different influences—say, unusual friends or special teachers. A cloned Albert Einstein might fail his physics class. A cloned pop star might sing terribly. Say you were cloned. Would your twin live a shorter life because he or she started out with DNA that was already 10, 20 or 30 years old? Scientists aren't sure. And how could you prevent someone from taking a sample of your hair and making a clone of you? Again, no solutions. What do you think? Should scientists be allowed to clone animals? How about humans?

单选题Lyndon B. Johnson (was) the only United States President (who) oath of (office) as (administered) by a woman Judge called Sarah Tilghman Hughes.

单选题Recent studies have identified four major global environmental risks; acid rain, ozone (臭氧) depletion, deforestation and the greenhouse effect.

单选题A: I'm sorry, but he's out to lunch right now. B: ______.

单选题(Thirteen hundred) medical professionals, (all of which) have been trained to treat drug dependency, (attended) the annual convention (sponsored) by a society.A. Thirteen hundredB. all of whichC. attendedD. sponsored

单选题Lack of confidence in his own abilities is the chief defect in Mike's character.

单选题I (saw that) the last update was made in (January of) 2002, so I (wondered that) the webmaster (had abandoned) the site.

单选题The new tenant (in) the apartment was (obviously) both (suspicious) and interested (in) his neighbors.

单选题As is known to all, a vague law is always ______to different interpretations.

单选题Over the centuries man has developed drugs that could cure or ______ illness and suffering.

单选题According to new research of Prof. Randolf Menzel from the Free University in Berlin, the popular image of bees as the ultimate hard workers was inaccurate. "Although we see bees buzzing around tirelessly in spring and summer, the common belief in a bee's busy nature is based on a misconception," he said. People only really see bees when they're out flying, or they look at a colony of bees and see thousands of them buzzing around. They don't get to pick them out as individuals. The professor, who this month won a German Zoological Society award for his work on bees, added that bees compensated for their apparent laziness with high intelligence, advanced memory skills and an ability to learn quickly. The suggestion that bees were not pulling their weight met with skepticism from British beekeepers. Glyn Davies, the President of the British Beekeepers Association, said that bees were not lazy but efficient. "At any particular stage in its life, a bee has a specific job to do. If they are unable to do that job, they conserve their energy by doing nothing. Each bee has a unit of life energy and the faster it works, the faster it dies. They are being very wise and perhaps humans should try to follow their example instead of running about like headless chickens. " The idea of the busy bee is several thousand years old. One current author who has nothing but admiration for the bee is Paul Theroux, the novelist and part-time beekeeper. "I have never seen a bee sleeping. My bees never stop working. " he said, Mr. Theroux, who keeps 85 hives each containing 30000 bees in Hawaii, added that Prof. Menzel's research could have been affected by his national origins. "Perhaps in comparison to the German rate of work, the bee does look lazy," he said. Few people think that the busy bee idea will go away, despite the efforts of Prof. Menzel. It performs too many useful functions in our culture. In fact, the worship of hees seems to be undergoing a renaissance. IBM recently ran a series of ads drawing on the " waggle dance" of bees, telling businessmen to "make your business waggle. /

单选题Readers are required to Ucomply with/U the rules of the library and mind their manners.

单选题The primary objective of Basic Econometrics is to provide an elementary but comprehensive introduction to the art and science of econometrics.

单选题{{B}}{{I}}Directions{{/B}}: There are five passages in this part. Each passage is followed by five questions or unfinished statements. For each of them there are four choices marked A, B, C and D. Choose the best one and mark the corresponding letter on the {{B}}ANSWER SHEET{{/B}} with a single line through the center.{{/I}} {{B}}Passage One{{/B}} Americans usually consider themselves a friendly people. Their friendships, however, tend to be shorter and more casual than friendships among people from other cultures. It is not uncommon for Americans to have only one close friend during their lifetime, and consider other "friends" to be just social acquaintances. This attitude probably has something to do with American mobility and the fact that Americans do not like to be dependent on other people. They tend to "compartmentalize" (划分) friendships, having "friends at work", "friends on the softball team", "family friends", etc.. Because the United States is a highly active society, full of movement and change, people always seem to be on the go. In this highly charged atmosphere, Americans can sometimes seem brusque (无礼的) or impatient. They want to get to know you as quickly as possible and then move on to something else. Sometimes, early on, they will ask you questions that you may feel are very personal. No insult is intended; the questions usually grow out of their genuine interest or curiosity, and their impatience to get to the heart of the matter. And the same goes for you. If you do not understand certain American behavior or you want to know more about them, do not hesitate to ask them questions about themselves. Americans are usually eager to explain all about their country or anything "American" in which you may be interested. So much so in fact that you may become tired of listening. It doesn't matter because Americans tend to be uncomfortable with silence during a conversation. They would rather talk about the weather or the latest sports scores, for example, than deal with silence. On the other hand, don't expect Americans to be knowledgeable about international geography or world affairs, unless those subjects directly involve the United States. Because the United States is not surrounded by many other nations, some Americans tend to ignore the rest of the world.

单选题It is stated in Paragraph 1 that the construction of a new education system ______