题目内容
第二篇 Shopping at Second-hand Clothing Stores When 33-year-old Pete Barth was in college, shopping at second-hand clothing stores was just something he did - "like changing the tires on his car." He looked at his budget, and decided he could save a lot of money by shopping for clothes at thrift shops. "Even new clothes are fairly disposable (用后即丢掉的) and wear out after a couple of years," Barth said. "In thrift shops, you can find some great stuff whose quality is better than new clothes." Since then, Barth, who works at a Goodwill thrift shop in the US state of Florida, has found that there are all kinds of reasons for shopping for second-hand clothing. Some people like him, shop to save money. Some shop for a crazy-looking shirt. And some hop as a means of conserving energy and helping the environment. Pat Akins, an accountant at a Florida Salvation Army (SA) (救世军) thrift shop, said hat, for her, shopping at thrift shops is a way to help the environment. "When my daughter was little, we looked at it as recycling," Akins said. "Also, why ay 30 dollars for a new coat when you can get another one for a lot less" Akins said that the SA has shops all over the US - "some as big as department stores." All of the clothes are donated (捐赠), and when they have a surplus (盈余), they’ll have "stuff a bag" specials, where customers can fill a grocery sack with clothes for only or 10 dollars. Julia Slocum, 22, points out, however, that the huge amount of second-hand clothing in the US is the result of American wastefulness. I’d say that second-hand stores are the result of our wasteful, materialistic culture," said Slocum, who works for a pro-conservation organization, the Center for a New American Dream. "Thrift shops prevent that waste from going to landfills (垃圾填埋场); they give clothing a second life, provide cheaper clothing for those who can’t afford to buy new ones and generate (生成) income for charities. They also provide a way for the wealthy and middle classes to shed (摆脱) some of the guilt for their level of consumption." When Barth was a college student, he often shopped at thrift shops
查看答案
搜索结果不匹配？点我反馈
更多问题
Radiocarbon Dating Nowadays scientists can answer many questions about the past through a technique called radiocarbon (放射性碳), or carbon-14, dating. One key to understanding how and by something happened is to discover when it happened. Radiocarbon dating was developed in the late 1940s by physicist Willard F. Libby at he University of Chicago. An atom of ordinary carbon, called carbon-12, has six protons(质子) and six neutrons (中子) in its nucleus(原子核). Carbon-14, or C-14, is a radioactive, unstable form of carbon that has two extra neutrons. It returns to a more stable form of carbon through a process called decay (衰减). This process involves the loss of he extra neutrons and energy from the nucleus. In Libby’s radiocarbon dating technique, the weak radioactive emissions (放射) from this decay process are counted by instruments such as a radiation detector and counter. The decay rate is used to determine the proportion of C-14 atoms in the sample being dated. Carbon-14 is produced in the Earth’s atmosphere when nitrogen (氮)-14, or N-14,interacts with cosmic rays (宇宙射线). Scientists believe since the Earth was formed, the mount of nitrogen in the atmosphere has remained constant. Consequently, C-14 formation is thought to occur at a constant rate. Now the ratio of C-14 to other carbon toms in the atmosphere is known. Most scientists agree that this ratio is useful for dating items back to at least 50,000 years. All life on Earth is made of organic molecules (分子) that contain carbon atoms coming from the atmosphere. So all living things have about the same ratio of C-14 atoms to other carbon atoms in their tissues (组织). Once an organism (有机体) dies it stops taking in carbon in any form, and the C-14 already present begins to decay. Over time the amount of C-14 in the material decreases, and the ratio of C-14 to other carbon atoms goes down. In terms of radiocarbon dating, the fewer C-14 atoms in a sample, the older that sample is. Nowadays many scientists depend on radiocarbon for dating age-old objects
第三篇 Water The second most important constituent (构成成份) of the biosphere (生物圈) is liquid water. This can only exist in a very narrow range of temperatures, since water freezes at 0℃ and boils at 100℃. Life as we know it would only be possible on the surface of a planet which had temperatures somewhere within this narrow range. The earth’s supply of water probably remains fairly constant in quantity. The total quantity of water is not known very accurately, but it is about enough to cover the surface of the globe to a depth of about two and three-quarter kilometers. Most of it is in the form of the salt water of the oceans about 97 percent. The rest is fresh, but three quarters of this is in the form of ice at the Poles and on mountains, and cannot be used by living systems until melted. Of the remaining fractional which is somewhat less than one per cent of the whole, there is 10—20 times as much stored underground water as there is actually on the surface. There is also a tiny, but extremely important fraction of the water supply which is present as water vapor in the atmosphere. Water vapor in the atmosphere is the channel through which the whole water circulation (循环) of the biosphere has to pass. Water evaporated (蒸发) from the surface of the oceans, from lakes and rivers and from moist (潮湿的) earth is added to it. From it the water comes out again as rain or snow, falling on either the sea or the land. There is, as might be expected, a more intensive evaporation per unit area over the sea and oceans than over the land, but there is more rainfall over the land than over the oceans, and the balance is restored by the runoff from the land in the form of rivers. The word "fraction" in the second paragraph means
Chimpanzees 1 Chimpanzees (黑猩猩) will soon be extinct (灭绝). If the present rate of hunting and habitat (栖息地) destruction continues, then within 20 years, there will be no chimpanzees living in the wild. But this is more than an environmental or moral tragedy (悲剧). Chimpanzee extinction may also have profound implications (含意) for the survival of their distant relatives - human beings. 2 In 1975 the biologist Marie-Claire King and Allan Wilson discovered that the human and chimpanzee genomes (基因组) match by over 98%. Compare this to the mouse, used as model for human disease in lab tests, which shares only 60% of its DNA with us. In fact, chimpanzees are far more similar to humans than they are to any other species of monkey. As well as resembling us genetically, chimps are highly intelligent and able to use tools. These facts alone should be enough to make protection of chimps an urgent priority (优先). But there is another, more selfish reason to preserve the chimp. 3 The chimpanzees’ trump card (王牌) comes in the field of medical research. Chimpanzees are so similar to humans that veterinarians (兽医) often refer to human medical textbooks when treating them. Yet chimpanzees do show differences in several key areas. In particular, chimps are much more resistant to a number of major diseases. It is this ability that is so interesting. 4 For example, chimps seem to show a much higher resistance than humans to HIV, the virus that causes AIDS. Indeed, their use as experimental animals in AIDS research has declined because they are so resistant. 5 By sequencing the chimp genome and pinpointing (找到) the place where the chimpanzee DNA sequence differs from that of humans, scientists hope to be able to discover which part of the genetic code gives chimps their increased resistance to some diseases. This, they hope, will allow them to develop new and more effective treatments for the human forms of these diseases. Such treatments could include the production of new drugs or even the alteration (改变) of the human genetic sequence. The recently completed human genome sequencing project has shown that such an effort is now well within our reach.23 Paragraph _____1.24 Paragraph _____2.25 Paragraph _____3.26 Paragraph _____4.A Reasons for HIV resistanceB Implications of chimpanzee extinction for humansC Effective AIDS treatmentD Genetic similarities between chimps and humansE Chimps’ resistance to HIVF Genetic differences between chimps and humans27 Chimpanzee extinction may affect28 There is a difference of less than 2% between the chimp and29 Scientists suspect that genes.PlaY a significant role in protecting chimps from getting30 The discovery of the genetic code of chimps will be helpful toA some human disease treatmentsB some diseasesC human survivalD human genomesE key areasF healthier lifestyle
One Good Reason to Let Smallpox Live It’s now a fair bet that we will never see the total extinction (灭绝) of the smallpox (天花) virus. When smallpox was completely got rid of in the world, scientists wanted to (51) the killer virus in the last two labs - one in the US and one in Russia. They asked: If smallpox has truly gone from the planet, (52) point was therein keeping these reserves in reality, of course, it was naive to (53) that everyone would let go of such a powerful potential weapon. Undoubtedly several nations still have (54) vials (小药瓶). And the last "official" stocks of live virus bred mistrust of the US and Russia, (55) no obvious gain. Now American researchers have (56) an animal model of the human disease, opening the (57) for tests on new treatments and vaccines (疫苗). So once again there’s a good reason to (58) the virus -just in (59) the disease puts in a reappearance. How do we (60) with the mistrust of the US and Russia (61) . Keep the virus (62) international support in a well-guarded UN laboratory that’s open to all countries. The US will object, of course, just as it (63) a multilateral (多边的) approach to just about everything. But it doesn’t mean the idea is (64) . If the virus is useful, then let’s (65) it the servant of all humanity not just a part of it.
微信支付 
支付宝支付