2022吉林公共英语考试模拟卷(5).docx
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1、2022吉林公共英语考试模拟卷(5)本卷共分为1大题50小题,作答时间为180分钟,总分100分,60分及格。一、单项选择题(共50题,每题2分。每题的备选项中,只有一个最符合题意) 1.Questions 1720 are based on the following talk. You now have 20 seconds to read Questions 1720.According to the speaker, how do some pesticides get into ponds A They are applied to aquatic weeds by fish far
2、ming. B Amphibians release them from their skin. C Irresponsible dispose of them in ponds. D They are washed into ponds by the rain. 2.Novel approaches to babymaking seem to be coming at us so fast that we hardly have time to digest one before the next one hits test-tube babies, egg donation, surrog
3、acy, cloning and now sex selection. And just as with earlier methods, the new sperm-separation technique announced last week has triggered plenty of ethical concern. Only a few critics have argued that tampering with nature to avoid a sex-linked genetic disease should be taboo. But plenty have expre
4、ssed misgivings about using the new technology more casually, to balance families, or simply because parents prefer boys or girls. Such choices, critics say, could lead to an imbalance in the sex ratio, with drastic consequences for society. These arguments are not very persuasive. In some developin
5、g countries where boys are more highly valued than girls, sex selection is already standard practice, accomplished by means of infanticide of amniocentesis and abortion. The new sperm-separation technique makes it easier for more people to practice sex selection in these countries. This could skew t
6、he already tilting sex radio even further in favor of boys. In the short term, such demographic shifts could cause enormous societal problems as men, for example, find it increasingly difficult to find women to marry. In the long term, however, both evolutionary and economic theories tell us that as
7、 girls become more scarce, they will become more highly valued, perhaps to the point at which more people will select for girls than against them. In America and other Western countries there seems to be little chance of the sexes going far out of balance at all. Polls show that a majority of Americ
8、ans view a perfect family as having one boy and one girl. If everyone used sex selection to achieve perfection, the result would be perfect balance. Of course, some prospective parents do prefer children of one sex or the other. But such preferences would presumably balance out as well. Regarding th
9、e argument that choosing gender goes against nature: the same objection was used in earlier times by people horrified by vaccines or heart transplants, which are now completely acceptable. Every time we use medicine to cure a disease or prevent a death, we go against nature willingly. Admittedly, se
10、x selection for family balancing cures no disease. In fact, though, no form of babymaking solves a medical problem. Sex selection, moreover, is medically bengin in comparison with most reproductive technologies. No surgery is involved, and the entire process can theoretically be performed without a
11、physician. Children born through this process cant be distinguished from other children. For these reasons, I suspect that as sex selection and other reproductive technologies become more efficient and less costly, they may be embraced by American families of even modest means who ask themselves, wh
12、y not What was once unimaginable could become routine and the link between the sex act and reproduction will no longer be seen as sacred. Ultimately, this may prove to be the real significance of sex selection: by breaching a powerful psychological barrier, it will pave the way for true designer bab
13、ies, who could really turn society upside down.Which of the following statements is true A The sexes go far out of balance in Western countries. B Perfect balance would not be achieved in view of an American perfect family. C Evolutionary and economic theories show no sign of an imbalance in sex rat
14、io. D It is high time for us to prevent sex selection from becoming routine. 3.A UCSF study has revealed new information about how the brain directs the body to make movements. The key factor is noise in the brains signaling, and it helps explain why all movement is not carried out with the same lev
15、el of precision. Understanding where noise arises in the brain has implications for advancing research in neuromotor control and in developing therapies for disorders where control is impaired, such as Parkinsons disease. The new study was developed to understand the brain machinery behind such comm
16、on movements as typing, walking through a doorway or just pointing at an object, says Stephen Lisberger, PhD, senior study investigator who is director of the W.M. Keck Center for Integrative Neuroscience at the University of California, San Francisco. Study co-investigators are Leslie C. Osborne, P
17、hD, a postdoctoral fellow at UCSF, and William Bialek, PhD, professor of physics at Princeton University. The study findings, reported in the September 15 issue of the journal Nature; are part of ongoing research by Lisberger and colleagues on the neural mechanisms that allow the brain to learn and
18、maintain skills and behavior. These basic functions are carried out through the coordination of different nerve cells within the brains neural circuits. To make a movement, the brain takes the electrical activity of many neurons and combines them to make muscle contractions, Lisberger explains. But
19、the movements arent always perfect. So we asked, what gets in the way The answer, he says, is noise, which is defined as the difference between what is actually occurring and what the brain perceives. He offers making a foul shot in basketball as an example. If there were no noise in the neuromotor
20、system, a player would be able to perform the same motion over and over and never miss a shot. Understanding how noise is reduced to very precise commands helps us understand how those commands are created, says Lisberger, who also is a Howard Hughes Medical Institute investigator and a UCSF profess
21、or of physiology. In the study, the research team focused on a movement that all primates are very skilled at: an eye movement known as smooth pursuit that allows the eyes to track a moving target. In a series of exercises with monkeys in which the animals would track visual targets, the researchers
22、 measured neural activity and smooth pursuit eye movements. From this data, the team analyzed the difference between how accurately the animals actually tracked a moving object and how accurately the brain perceived the trajectory. Findings showed that both the smooth pursuit system and the brains p
23、erceptual system were nearly equal. This teaches us that these very different neural processes are limited to the same degree by the same noise sources, says Lisberger. And it shows that both processes are very good at reducing noise. He concludes, Because the brain is noisy, our motor systems dont
24、always do what it tells us to. Making precise movements in the face of this noise is a challenge.How does noise affect a basketball players performance A It helps him hit the target every time. B It makes him a perfect player. C It makes him miss the shot sometimes. D It allows him to follow the bra
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