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World leaders met recently at United Nations headquarters in New York City to discuss the environmental issues raised at the Rio Earth Summit in 1992．The heads of state were supposed to decide what further steps should be taken to halt the decline of Earth’s life-support systems．In fact，this meeting had much the flavour of the original Earth Summit．To wit：empty promises，hollow rhetoric，bickering between rich and poor，and irrelevant initiatives．Think U.S. Congress in slow motion． The writer’s general attitude towards the world leaders meeting at the UN is______． [A] supportive [B] impartial [C] critical [D] comedic

Almost obscured by this torpor is the fact that there has been some remarkable progress over the past five years—real changes in the attitude of ordinary people in the Third World toward family size and a dawning realisation that environmental degradation and their own well-being are intimately，and inversely，linked．Almost none of this，however, has anything to do with what the bureaucrats accomplished in Rio．
B. Or it didn’t accomplish．One item on the agenda at Rio，for example，was a renewed effort to save tropical forests．(A previous UN-sponsored initiative had fallen apart when it became clear that it actually hastened deforestation．)After Rio，a UN working group came up with more than 100 recommendations that have so far gone nowhere．One proposed forestry pact would do little more than immunizing wood-exporting nations against trade sanctions． An effort to draft an agreement on what to do about the climate changes caused by CO2 and other greenhouse gases has fared even worse．Blocked by the Bush Administration from setting mandatory limits，the UN in 1992 called on nations to voluntarily reduce emissions to 1990 levels．Several years later，it’s as if Rio had never happened．A new climate treaty is scheduled to be signed this December in Kyoto，Japan，but governments still cannot agree on these limits．Meanwhile，the U.S. produces 7% more CO2 than it did in 1990，and emissions in the developing world have risen even more sharply．No one would confuse the“Rio process”with progress．
C. While governments have dithered at a pace that could make drifting continents impatient，people have acted．Birth-rates are dropping faster than expected，not because of Rio but because poor people are deciding on their own to reduce family size．Another positive development has been a growing environmental consciousness among the poor．From slum dwellers in Karachi，Pakistan，to colonists in Rondonia，Brazil，urban poor and rural peasants alike seem to realize that they pay the biggest price for pollution and deforestation．There is cause for hope as well in the growing recognition among business people that it is not in their long-term interest to fight environmental reforms．John Browne，chief executive of British Petroleum，boldly asserted in a major speech in May that the threat of climate change could no longer be ignored．

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A UCSF study has revealed new information about how the brain directs the body to make movements. The key factor is "noise" in the brain’s signaling, and it helps explain why all movement is not carried out with the same level 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 Parkinson’s disease. The new study was developed "to understand the brain machinery behind such common 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, PhD, 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 maintain skills and behavior. These basic functions are carried out through the coordination of different nerve cells within the brain’s 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 the movements aren’t 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 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 professor 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 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 brain’s perceptual 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 don’t always do what it tells us to. Making precise movements in the face of this noise is a challenge.\ Of the following movements instructed by the brain, which one is not mentioned in the article

A. [A] Pointing at an object.
B. Jogging.
C. Walking through a doorway.
D. Typing.

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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, surrogacy, 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 expressed 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 developing 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 the 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 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 Americans 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 the 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, sex 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 physician. Children born through this process can’t 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, why 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 babies, who could really turn society upside down. Which of the following is not a worry to many people about new ways of babymaking

A. [A] Sex selection goes against nature.
B. Choosing gender leads to an imbalance in the sex ratio.
C. Preference of a boy over a girl will be terrible for society.
D. It is impossible to avoid a sex-linked genetic disease.

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Questions 17～20 are based on the following talk. You now have 20 seconds to read Questions 17～20. What does the speaker mainly discuss

A. [A] The distribution of different species of amphibians.
B. Possible reasons for reduction in the number of amphibians.
C. The effects of environmental change on the fish industry.
D. Guidelines for the responsible use of pesticides.

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某投资公司建造一幢办公楼，采用公开招标方式选择施工单位。招标文件要求：提交投标文件和投标保证金的截止时间为2009年5月30日。该投资公司于2009年3月6日发出招标公告，共有5家建筑施工单位参加了投标。第5家施工单位于2009年6月2日提交了投标保证金。开标会于2009年6月3日由该省建委主持。第4家施工单位在开标前向投资公司要求撤回投标文件和退还投标保证金。经过综合评选，最终确定第2家施工单位中标。投资公司(甲方)与中标单位(乙方)双方按规定签订了施工承包合同，合同约定开工日期为2009年8月16日。工程开工后发生了如下几项事件。事件一：因拆迁工作拖延，甲方于2009年8月18日才向乙方提供施工场地，导致乙方A、B两项工作延误了2天，并分别造成人工窝工6个和8个工日；但乙方C项工作未受影响。事件二：乙方与机械设备租赁商约定，D项工作施工用的某机械应于2009年8月28日进场，但因出租方原因推迟到当月29日才进场，造成D工作延误1天和人工窝工7个工日。事件三：因甲方设计变更，乙方在E项工作施工时，导致人工增加14个工日，相关费用增加了1.5万元，并使施工时间增加了2天。事件四：在F项工作施工时，因甲方供材出现质量缺陷，乙方施工增加用工6个工日，其他费用1000元，并使H项工作时间延长1天，人工窝工24个工日。上述事件中，A、D、H三项工作均为关键工作，没有机动时间，其余工作均有足够的机动时间。[问题] 乙方能否就上述每项事件向甲方提出工期索赔和费用索赔？请说明理由。

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