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合同法律关系是由主体、客体、标的物三个要素构成的。
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What should be done if one wants to gain or lose weight The process of gaining or losing weight can be explained by comparing your body to your car. Both run 1 fuel, food for your body and gasoline for your car. Both 2 that fuel, first into heat, then energy, some of 3 is used to do work, and some emitted as waste. And 4 your car uses more energy when the engine is racing than when it is idling, 5 does your body use more energy when you are working hard than 6 you are resting. For the purpose of this comparison, 7 , there is one significant difference between them. Your car cannot store fuel by turning it into 8 else; all gasoline not 9 remains as gasoline. But your body stores 10 energy as fat. When the gas tank is 11 empty, the car won’t run; but your body can burn fat to provide more energy. Therefore, if you want to gain weight, you must do 12 of two things: eat more calories (units of heat, therefore energy), or use less through 13 . If you want to lose weight, you do the 14 , decrease your intake of calories or increase the amount of energy you spend. There is 15 way. Gaining or losing weight is always a relation between intake and output of potential energy.
Genocide Many people feel that human beings are responsible for the disappearance of some other animal species. While we may have hastened the disappearance of some, abundant evidence suggests mankind has had little impact. Biologists point out that 50 species can be expected to disappear in the twentieth century but also remind us that about 50 species can be expected in the nineteenth century, and 50 species in each of the centuries before that. Dr. T.H. Jukes at the University of California has pointed out that about 100 million animal species have become extinct since life began on Earth about 3 billion years ago. Thus, animals come and animals go as a natural consequence of something Mr. Darwin discovered. The human race is a recent newcomer to the scene, so we’ve had nothing whatsoever to do with the disappearance of millions of species. In fact, when it comes right down to it, we’re a miserable failure at genocide (种族灭绝). In spite of an all-out centuries-old war on rats, we haven’t made a dent in their numbers, much less extinguished a single species. And in spite of all our high technology we haven’t been successful in eliminating a single undesirable insect species! A friend of mine owns most of the Douglas DC-7 aircrafts left in the world. They make excellent spray planes because they can carry a lot of insecticide and fly for a very long time over great distances. Last year, his company sprayed most of the western Sahara and the Sahel regions of Africa to hold down the locusts and grasshoppers. This year, the environmentalists put pressure on the U.N. to stop it because dieldrin and malathion might cause an increase in the cancer risk of people in the western Sahara and the Sahel. As a result, the hoppers and locusts are back by the zillions and the crops are failing. But the people of West Africa certainly aren’t going to worry about dying of cancer; they are dying of starvation instead. I’ve come to the conclusion that the people who are trying to save the world are probably quite sincere about it but they don’t know much about science and certainly nothing about systems engineering. Which of the following is closest in meaning to the phrase "made a dent in their numbers" (Sentence 2, para. 2)
Continue to Protect or Destroy Ecosystem Biosphere Ⅱ was a spectacular failure. The gleaming glass-and-concrete habitat sprawling across the desert in Oracle, Arizona, was supposed to support eight human "biospherians" for two years. But the seal has to he broken before the experiment ended in 1993. Oxygen had fallen to levels normally seen at an elevation of 17,500 feet. Nitrous oxide had risen to the point where it threatened to cause brain damage. The fresh water supply became contaminated, and vines smothered (厚厚地覆盖) food plants. Insect pollinators (传授花粉的生物) and many other species became extinct. By the end, Biosphere Ⅱ was overrun with swarms of ants and cockroaches. Scientists who gathered recently to review the Biosphere Ⅱ experiment reached a disturbing conclusion: "No one yet knows how to engineer systems that provide humans with the life-supporting services that natural ecosystems produce for free." The problem is that these ecosystems are undergoing wrenching changes. Water and air quality, while improving in some regions, are deteriorating in many others. Carbon dioxide levels in the atmosphere arc climbing. The world’s population could reach 10 billion by 2050. And famed Harvard biologist Edward O. Wilson says the current rate of species losses puts us "in the midst of one of the great extinction spasms (突然进发) of geological history." All of which makes many ecologists wonder whether humans too will soon become extinct. It’s an incredibly important but incredibly difficult question. If we continue on this course, we’re heading for a world in which we will have to engineer services we’ve always received for free from nature. That’s why the failure of Biosphere Ⅱ was so disturbing: it proves that we don’t yet know how to do that. The Biosphere Ⅱ experience demonstrated that maintaining human life is a tricky proposition-especially if we can no longer rely on the services provided by natural ecosystems. If we are currently living through a mass extinction, as Wilson believes, we should consider the past. In the great Permian extinction 245 million years ago, 96 percent of species perished. Eventually, the Earth was repopulated with a rich collection of new species, but it took 100 million years. "That should give pause to anyone who believes that what Homo sapiens (现代人) destroys, nature will redeem," Wilson says. "Maybe so, but not within any length of time that has meaning for contemporary humanity." The seal of the Biosphere Ⅱ had to he broken before the experiment ended because ______.
Cloning (克隆): Future Perfect 1. A clone is an exact copy of a plant or animal produced from any one cell. Since Scottish scientists reported that they had managed to clone a sheep named Dolly in 1997 research into cloning has grown rapidly. In May 1998, scientists in Massachusetts managed to create WTO identical calves (牛犊) using cloning technology. A mouse has also been cloned successfully, but the debate over cloning humans really started when Chicago physicist Richard Seed made a surprising announcement: "We will have managed to clone a human being within the next two years," he told the world. 2. Seed’s announcement provoked a lot of media attention, most of it negative. In Europe, nineteen nations have already signed an agreement banning human cloning and in the U.S. the President announced: "We will be introducing a law to ban any human cloning and many states in the U.S. will have passed anti--cloning laws by the end of the year." 3. Many researchers are not so negative about cloning. They are worried that laws banning human cloning will threaten important research. In March, The New England Journal of Medicine called any plan to ban research on cloning humans seriously mistaken. Many researchers also believe that in spite of attempts to ban it, human cloning will have become routine by 2010 because it is impossible to stop the progress of science. 4. Is there reason to fear that cloning will lead to a nightmare world The public has been bombarded (轰炸) with newspaper articles, television shows and films, as well as cartoons. Such information is often misleading, and makes people wonder what on earth the scientists will be doing next. 5. Within the next five to ten years scientists will probably have found a way of cloning humans. It could be that pretty soon we will be able to choose the person that we want our child to look like. But how would it feel to be a clone among hundreds, the anti-cloners ask. Pretty cool, answer the pro-cloners (赞成克隆的人). A. Strong Reactions B. Anxiety about the Future of Cloning C. The Right to Choose D. What is Cloning E. Arguments in Favor of Cloning F. A Common Sight Paragraph 1 ______.
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