阅读理解。 We have seen that pesticides (杀虫剂) now pollute soil, water and food, and that they have the power to make our rivers fishless and our gardens and woodlands silent and birdless. Man, however much he may like to pretend the opposite, is part of nature. Can he escape a pollution that is now so thoroughly spread throughout our world? We know that even single exposure to these chemicals, if the amount is large enough, can cause extremely severe poisoning. But this is not the major problem. The sudden illness or death of farmers, farm workers and others exposed to enough quantities of pesticides is very sad and should not happen. For the population as a whole, we must pay more attention to the delayed effects of taking in small amounts of the pesticides that unseeably pollute our world. Responsible public health officials have pointed out that the biological effects of chemicals are increasing in amount over long periods of time, and that the danger to the man may depend on the amount of the exposures received throughout his lifetime. For these very reasons people easily take no notice of the danger. It is human nature to shake off what may seem to us a future disaster. 'Men are naturally most impressed by diseases which have obvious signs,' says a wise physician, Dr. Rene Dubos, 'yet some of their worst enemies slowly come near them unnoticed.' 62. Which of the following can best summarize the first paragraph of this passage? A. Man has a responsibility to bear for what has happened to nature. B. Possibly man will escape the effects of environmental pollution. C. Pesticide-caused pollution may also kill people. D. Man acts as if he did not belong to nature. 2. People do not give enough attention to the delayed effects of exposure to chemicals because _____. A. limited exposure to them does little harm to people's health B. the present is more important to them than the future C. humans are able to bear small amounts of poisoning D. the danger does not become seen clearly and immediately 3. Which of the following statements is true according to the passage? A. A person exposed to pesticides even once may get seriously poisoned. B. Birds are less sensitive to pesticides than humans. C. The effects of pesticides on humans do not last as long as on fish. D. Taking in small amounts of pesticides will not cause serious results. 4. We can conclude from what Dr Dubos says that _____. A. people usually find hidden diseases difficult to deal with B. people fail to notice hidden dangers caused by pesticides C. diseases with obvious signs are mostly easy to cure D. attacks by hidden enemies are likely to be deadly