单选题阅读下面的短文，文中有15处空白，每处空白给出4个选项，请根据短文的内容从4个选项中选择1个最佳答案。 Taking a cell, practically any cell, from your body, the theory goes, and through appropriate biological tinkering(摆弄) you can cause it to grow into a duplicate of yourself—identical from eyelashes to toenails. No need for procreational(生育的) sex any more;{{U}} (51) {{/U}}this system, you can neatly reproduce yourself without a{{U}} (52) {{/U}}. Human cloning, it is called. Science fact or science fiction? What would happen if human cloning became a{{U}} (53) {{/U}}? One favorite scenario is the{{U}} (54) {{/U}}of a new{{U}} (55) {{/U}}of Hitlers—or Einsteins. Scientists quickly disclaim the possibility. "It is more than genetic make-up that makes an individual." Says Markert of Yale University, "We are all products of a particular{{U}} (56) {{/U}}era and of a special environment, with so many minute things{{U}} (57) {{/U}}the way we develop each and every day, even in the womb, that a duplicate background--and therefore a duplicate{{U}} (58) {{/U}}could never be created." Already biologists studying the cell's{{U}} (59) {{/U}}workings and the various methods of cloning have made discoveries that may ultimately lead to breakthroughs{{U}} (60) {{/U}}the fight against cancer, control of the aging process, and the conquest of more than 100 presently incurable human genetic diseases. To{{U}} (61) {{/U}}cloning-related research would mean closing the door{{U}} (62) {{/U}}and important area of knowledge. To continue to probe the secrets of the cell, however, is perhaps to{{U}} (63) {{/U}}the secret of human cloning. And, given the nature of man, if it can be done it will be done. What then is the{{U}} (64) {{/U}}? Says Congressman Rogers: "It is clear that human cloning is not yet possible. The day when it will be—if ever—is far{{U}} (65) {{/U}}. For now, at least, the benefits of cell-biology research outweigh the risks."

单选题The use of the chemical may present a certain hazard to the laboratory workers.

单选题Some birds {{U}}consistently{{/U}} return to the same nesting area each spring.

单选题 Something Men Do Not Like to Do Eric Brown hates shopping. "it's just not enjoyable to me," said the 2g-year-old Chicago man who was carrying several shopping bags along the city's main street, Michigan Avenue. "When I'm out {{U}} {{U}} 1 {{/U}} {{/U}}, I basically know what I want to get. I rush in. I buy it. I {{U}} {{U}} 2 {{/U}} {{/U}}." Common wisdom says that guys hate to shop. You can ask generations of men. But people who study shopping say that a number of social, cultural and economic factors are now {{U}} {{U}} 3 {{/U}} {{/U}}this "men-hate-to-shop" notion. "{{U}} {{U}} 4 {{/U}} {{/U}}social class, ethnicity, age, men say they hate to shop," says Sharon Zukin, a City University of New York sociology professor. "Yet when you ask them deeper questions, it turns out that they {{U}} {{U}} 5 {{/U}} {{/U}}to shop. Men generally like to shop for {{U}} {{U}} 6 {{/U}} {{/U}}, music and hardware. But if you ask them about the shopping they do for books or music, they'll say, 'Well that's not shopping. That's {{U}} {{U}} 7 {{/U}} {{/U}}'" In other words, what men and women call "buying things" and how they approach that task are {{U}} {{U}} 8 {{/U}} {{/U}}. Women will {{U}} {{U}} 9 {{/U}} {{/U}}through several 1,000-square-metre stores in search of the perfect party dress. Men will wander through 100 Internet sites in search of the {{U}} {{U}} 10 {{/U}} {{/U}}digital camcorder. Women see shopping as a social event. Men see it as a mission or a {{U}} {{U}} 11 {{/U}} {{/U}}to be won. "Men are frequently shopping to win," says Mary Ann McGrath, a marketing professor at Loyola University of Chicago, "they want to get the best deal. They want to get the best one, the last one and if they do that it {{U}} {{U}} 12 {{/U}} {{/U}}them happy." When women shop, "they're doing it in a way where they want {{U}} {{U}} 13 {{/U}} {{/U}}to be very happy," says McGrath. "They're kind of shopping for love." In fact, it is in clothing where we see a male-female {{U}} {{U}} 14 {{/U}} {{/U}}most clearly. Why, complain some men, are all male clothes navy, grey, black or brown? But would they wear light green and pink? These days, many guys wear a sort of "uniform", says Paco Underhill, author of Why We Buy, "It's been hard for them to understand what it means to be fashion-conscious in a business way. It becomes much, much easier if you {{U}} {{U}} 15 {{/U}} {{/U}}your range of choices."

单选题Our party is perfect with our great effortsA. excellentB. normalC. commonD. casual

单选题The new theory was {{U}}corroborated{{/U}}.

单选题The osprey flies above the water and when it spots a fish it swoops down to catch it.

单选题The quality and number of a city's public roads offer an excellent means of gauging its prosperity. A. protecting B. creating C. judging D. tracing

单选题 下面的短文有15处空白，请根据短文内容为每处空白白确定1个最佳选项。 It sounds all wrong-drilling holes in a piece of wood to make it more resistant to knock. But it works because the energy from the blow gets distributed throughout the wood rather than focusing on one weak spot. The discovery should lead to more effective and lighter packaging materials. Carpenters have known {{U}}(51) {{/U}} centuries that some woods are tougher than others. Hickory(山核桃木), for example, was turned into axe handles and cartwheel spokes (车轮辐条) because it can absorb shocks without breaking. White oak (橡木), for example, is much more easily damaged, {{U}}(52) {{/U}} it is almost as dense. Julian Vincent at Bathe University and his team were convinced the wood's internal structure could explain the differences. Many trees have tubular(管状的) vessels that run {{U}}(53) {{/U}}the trunk and carry water to the leaves. In oak they are large, and arranged in narrow bands, but in hickory they are smaller, and more evenly distributed. The researchers {{U}}(54) {{/U}} this layout might distribute a blow's energy throughout the wood, soaking up a bigger hit. To test the idea, they drilled holes 0.65 millimeters across into a block of spruce(云杉), a wood with {{U}}(55) {{/U}} vessels, and found that {{U}}(56) {{/U}}withstood a harder knock. {{U}}(57) {{/U}} when there were more than about 30 holes per square centimeter did the wood's performance drop off. A uniform substance doesn't cope well with knocks because only a small proportion of the material is actually {{U}}(58) {{/U}}. All the energy from the blow goes towards breaking the material in one or two places, but often the pieces left {{U}}(59) {{/U}} are pristine(未经破坏的). "But instead of the energy being concentrated in one place, the holes provide many weak spots that all absorb energy as they break", says Vincent, "You are controlling the places{{U}} (60) {{/U}} the wood breaks, and it can then absorb more {{U}}(61) {{/U}}, more safely". The researchers believe the principle could be applied to any material-{{U}} (62) {{/U}} example, to manufacture lighter and more protective packaging. That could {{U}}(63) {{/U}}be used in car bumpers (保险杠), crash barriers and armor for military vehicles, says Ulrike Wegst, {{U}}(64) {{/U}}the Max Plank Institute for Mental Research in Stuttgart. But she emphasizes that you'd{{U}} (65) {{/U}} to design the substance with the direction of force in mind. "The direction of loading is crucial", she says.

单选题Rockets in the Sky If someone asked you, "What color is the sky?" I expect that you would answer, "Blue." I am afraid that you would be wrong. The sky has no color. When we see blue, we are looking at blue sunlight. The sunlight is shining on little bits of dust in the air. We know that there is air all around the world. We could not breathe without air. Airplanes could not fly without air. They need air to lift their wings. Airplanes cannot fly very high because as they go higher the air gets thinner. If we go far enough away from the earth, we find there is no air. What is the sky? The sky is space. In this space there is nothing except the sun, the moon and all the stars. Scientists have always wanted to know more about the other worlds in the space. They have looked at them through telescopes and in this way they have found out a great deal. The moon is about 384,000 kilometers away from the earth. An airplane cann"t fly to the moon but there is a thing that can fly even when there is no air. This is rocket. I am sure that you are asking, "How does a rocket fly?" If you want to know, get a balloon and then blow it up until it is quite big. Do not tie up the neck of the balloon. Let go! The balloon will fly off through the air very quickly. The air inside the balloon tries to get out. It rushes out through the neck of the balloon and this pushes the balloon through the air. It does not need wings like an airplane. This is how a rocket works. It is not made of rubber (橡胶) like a balloon, of course. It is made of metal. The metal must not be heavy but it must be very strong. There is gas inside the rocket which is made very hot. When it rushes out of the end of the rocket, the rocket is pushed up into the air. Rockets can fly far out into space. Rockets with men inside them have already reached the moon. Several rockets, without men inside them, have been sent to other worlds much farther away. One day rockets may be able to go anywhere in the space.

单选题Mad Scientist Stereotype Outdated Do people still imagine a physicist as a bearded man in glasses or has the image of the mad scientist changed? The Institute of Physics set out to find out whether the stereotype of a physics "boffin" (科学家) still exists by conducting a survey on shoppers in London. The people were asked to identify the physicist from a photograph of a line-up of possible suspects. 98 percent of those asked got it wrong. The majority of people picked a white male of around 60, wearing glasses and with a white beard. While this stereotype may have been the image of an average physicist fifty years ago, the reality is now very different. Since 1960 the number of young women entering physics has doubled and the average age of a physicist is now 31. The stereotype of the absent-minded scientist has lasted a long time because the media and Hollywood help promote the image of men in white lab coats with glasses sitting by blackboards full of equations (等式) or working with fizzing (嘶嘶响) test tubes. These stereotypes are really damaging to society. Very good school children are put off studying science because they don"t see people like themselves on television or in magazines doing science. They simply don"t relate to the media"s image of the mad scientist. This is one reason why fewer young people are choosing to do science at university. If we want to encourage more young people to study science subjects, we need to change this image of the scientist and make science careers more attractive. But we must also develop children"s interest in science. In an attempt to change this negative image, an increasing number of science festivals are being organized. Thousands of people from secondary school are also encouraged to take part in nationwide science competitions, of which the most popular are the National Science Olympiads. Winning national teams then get the opportunity to take part in the International Science Olympiads which are held in a different country every year. These events are all interesting for the young people who take part in but they only involve a small proportion of students who are already interested in science. It seems that there is a long way to go before science becomes attractive as subjects like computer studies or fashion and design.

单选题The behavior is stemmed from his idea.A. flowsB. comesC. watchesD. observe

单选题Radiation Effect Space is a dangerous place, not only because of meteors (流星)but also because of rays from the sun and other stars. The atmosphere again acts as our protective blanket on earth light, gets through, and this is essential for plants to make the food that we eat. Heat, too, makes our environment endurable. Various kinds of rays come through the air from outer space, but enormous quantities of radiation from the sun are screened off. As soon as men leave the atmosphere they are exposed to this radiation, but their spacesuits or the walls of their spacecrafts, if they are inside, do prevent a lot of radiation damage. Radiation is the greatest known danger to explorers in space. The unit of radiation is called "rem" (“雷姆”). Scientists have reason to think that a man can put up with far more radiation than 0.1 rem without being damaged, the figure of 60 reins has been agreed on. The trouble is that it is extremely difficult to be sure about radiation damage-a person may feel perfectly well, but the cells of his or her sex organs may be damaged ,and this will not be discovered until the birth of deformed(畸形的)children or even grandchildren. Missions of the Apollo flights have had to cross belts of high radiation and, during the outward and return journeys, the Apollo crew accumulated a larger amount of reins. So far, no dangerous amounts of radiation have been reported, but the Apollo missions have been quite short. We simply do not know yet how men are going to get on when they spend weeks and months outside the protection of the atmosphere, working in a space laboratory. Drugs might help to decrease the damage clone by radiation ,but no really effective ones have been found so far.

单选题Television Is Doing lrrearable Harm "Yes, but what did we use to do before there was television?" How often we hear statements like this! Television hasn't been with us all that long, but we are already beginning to forget what the world was like without it, Before we admitted the one-eyed monster into our homes we never found it difficult to occupy our spare time. We used to enjoy civilized pleasures. For instance, we used to have hobbies, we used to entertain our friends and be entertained by them, we used to go outside for our amusements to theatres, cinemas, restaurants and sporting events, We even used to read books and listen to music and broadcast talks occasionally. All that belongs to the past. Now all our free time is regulated by the "goggle box". We rush home or gulp down our meals to be in time for this or that programme. We have even given up sitting at table and having a leisurely evening meal, exchanging the news of the day. A sandwich and a glass of beer will do anything, providing it doesn't interfere with the programme. The monster demands absolute silence and attention. If any member of the family dares to open his mouth during a programme, he is quickly silenced. Whole generation are growing up addicted to the telly. Food is left uneaten, homework undone and sleep is lost, The telly is a universal pacifier. It is now standard practice for mother to keep the children quiet by putting them in the living room and turning on the set. It doesn't mater that the children will watch rubbishy commercials or spectacles of sadism(性虐狂)and violence—so long as they are quiet. There is a limit to the amount of creative talent available in the world, Every day, television consumes vast quantities of creative work, That is why most of the programmes are so bad : it is impossible to keep pace with the demand maintain high standards as well. When millions watch the same programme, the whole world becomes a village, and society is reduced to the conditions which obtain in pre-literate communities (有文字之前的时期). We become utterly dependent on the two most primitive media of communication: pictures and the spoken work. Television encourages passive enjoyment. We become content with second-hand experiences. It is so easy to sit in our armchair watching others working. Little by little "television" cuts us off from the real world. We get so lazy, we choose to spend a fine day in semi-dark-ness, glued to our sets, rather than go out into the world itself, Television may be a splendid medium of communication, but it prevents us from communicating with each other. We only become aware how totally irrelevant television is to real living when we spend a holiday by the sea or in the mountains, far away from civilization, In quiet natural surroundings we quickly discover how little we miss the hypnotic (催眠)tyranny of King Telly.

单选题Her life is becoming more diverse .

单选题The Minister Uadmitted unwillingly/U that his Department had been "remiss".

单选题At 80, Peck was still vigorous and living in Paris.

单选题The study also notes a {{U}}steady{{/U}} decline in the number of college students taking science courses. A. relative B. continuous C. general D. sharp