We know that even single exposures to these chemicals, if the amount is large enough, cancause extremely severe poisoning. But this is not the major problem. The sudden illness ordeath of farmers, farmworkers, and others exposed to sufficient quantities of pesticides isvery sad and should not occur. For the population as a whole, we must be more concernedwith the delayed effects of absorbing small amounts of the pesticides that invisibly pollute ourworld.

　　Responsible public health officials have pointed out that the biological effects of chemicals arecumulative over long periods of time, and that the danger to individual may depend on thesum of the exposures received throughout his lifetime. For these very reasons the danger iseasily ignored. It is human nature to shake off what may seem to us a threat of futuredisaster. "Men are naturally most impressed by diseases which have obvious signs, " says awise physician, Dr Rene Dubos, "yet some of their worst enemies slowly approach themunnoticed."

　　練習題：

　　Choose correct answers to the question:

　　1.Which of the following is closest in meaning to the sentence "Man…is part of nature" (Para. 1, Lines 3-4)?

　　A. Man appears indifferent to what happens in nature.

　　B. Man acts as if he does not belong to nature.

　　C. Man can avoid the effects of environmental pollution.

　　D. Man can escape his responsibilities for environmental effects of pesticides?

　　2. What is the author"s attitude toward the environmental effects of pesticides?

　　A. Pessimistic

　　B. Indifferent

　　C. Defensive

　　D. Concerned

　　3. In the author"s view, the sudden death caused by exposure to large amounts ofpesticides _____.

　　A. is not the worst of the negative consequences resulting from the use of pesticides

　　B. now occurs most frequently among all accidental deaths

　　C. has sharply increased so as to become the center of public attention

　　D. is unavoidable because people can"t do without pesticides in farming

　　4. People tend to ignore the delayed effects of exposure to chemical because _____.

　　A. limited exposure to them does little harm to people"s health

　　B. the present is more important for them than the future

　　C. the danger does not become apparent immediately

　　D. humans are capable of withstanding small amounts of poisoning

　　5. It can be concluded from Dr. Dubos remarks that _____.

　　A. people find invisible diseases difficult to deal with

　　B. attacks by hidden enemies tend to be fatal

　　C. diseases with obvious signs are easy to cure

　　D. people tend to overlook hidden dangers caused by pesticides

　　1.[B] 題干的句子是文章第1段第3句，這是一個帶有插入語的簡單句，contrary在此表示跟part of nature相反，因此答案為B。

　　2.[D] 第2段最后一句提到，我們必須更加關注吸收少量殺蟲劑的潛在后果，它們正在不知不覺地污染我們的世界。因此，作者對殺蟲劑對環(huán)境的影響關注且擔憂,D符合題意。

　　3.[A] 第2段第2句提到，殺蟲劑使人突然發(fā)病或者死亡是很令人難過的亊，對于人口整體來說，人類對殺蟲劑長期累計的潛在后果的認識不足，才是最嚴重的問題，故選A。

　　4.[C] 根據(jù)第3段倒數(shù)第2句說的“對未來的災難無動于衷是人的本性”以及最后一句說的"大多數(shù)人只對有明顯跡象的疾病予以關注”可知C正是人們忽視化學藥物的潛在危害的原因，故選C。

　　5.[D] Dubos博士話中“最可怕的敵人”指的是“殺蟲劑引起的潛在危險”，博士話中的slowly approach themunnoticed直接表明D正確。

　　Just seven years ago, the Jarvik-7 artificial heart was being cheered as the model of humancreativeness. The sight of Barney Clark-alive and conscious after trading his diseased heart fora metal-and-plastic pump-convinced the press, the public and many doctors that the futurehad arrived. It hadn’t. After monitoring production of the Jarvik-7, and reviewing its effects onthe 150 or so patients (most of whom got the device as a temporary measure) the U.S.Food and Drug Administration concluded that the machine was doing more to endanger livesthan to save them. Last week the agency cancelled its earlier approval, effectively banning (禁止) the device.

　　The recall may hurt Symbion Inc., maker of the Jarvik-7, but it won’t end the request for anartificial heart. One problem with the banned mode is that the tubes connecting it to anexternal power source createda passage for infection. Inventors are now working on newdevices that would be fully placed, along with atiny power pack, in the patient’s chest. The firstsample products aren’t expected for another 10 or 20 years. But some people are alreadyworrying that they’ll work—and that America’s overextended health—care programs will lose aprecious $2.5 billion to $5 billion a year providing them for a relatively few dying patients. Ifsuch expenditures (開支) cut into funding for more basic care, the net effect could actually be adecline in the nation’s health.

　　練習題：

　　Choose correct answers to the question:

　　1. According to the passage, the Jarvik-7 artificial heart proved to be _____.

　　A. a technical failure

　　B. a technical wonder

　　C. a good life-saver

　　D. an effective means to treat heart disease

　　2. From the passage we know that Symbion Inc. _____.

　　A. has been banned by the government from producing artificial hearts

　　B. will review the effects of artificial hearts before designing new models

　　C. may continue to work on new models of reliable artificial hearts

　　D. can make new models of artificial hearts available on the market in 10 to 20 years

　　3. The new models of artificial hearts are expected ______.

　　A. to have a working life of 10 or 20 years

　　B. to be set fully in the patient's chest

　　C. to be equipped with an external power source

　　D. to create a new passage for infection

　　4. The word "them" in Line 7, Para. 2 refers to _____.

　　A. doctors who treat heart diseases

　　B. makers of artificial hearts

　　C. America's health-care programs

　　D. New model of artificial hearts

　　5. Some people feel that ______.

　　A. artificial hearts are seldom effective

　　B. the country should not spend so much money on artificial hearts

　　C. the country is not spending enough money on artificial hearts

　　D. America's health-care programs are not doing enough for the nation's health

　　1.[A] 文章一開頭說Jarvik-7以前被認為是一大技術成就，但文章第1段倒數(shù)第2句中提到,美國食品與藥品管理局得出結論,認為這種儀器與其說是挽救生命,不如說是將生命置于更加危險的境地。由此可知Jarvik-7是一個技術失敗,故選A。

　　2.[C] 文章第2段第1句提到，要求生產人造心臟的Symbion公司召回其銷售的人造心臟，這對該公來說或許是一種損失，但這一禁令不會終結人們對人造心臟的需求。從這一句可推斷出應選C。原文只提到政府禁止Jarvik-7這種型號的人造心臟，A把范圍擴大到了所有的人造心臟;B在原文中并未提及;D說的對象不是Symbion公司，也可排除。

　　3.[B] 文章中第2段第3句提到，這種新儀器可以完全置于患者的胸腔內，B與之相符，故選B。A在文中并未提及;C、D說的對象是Jarvik-7，故也排除。

　　4.[D] 從句子意思看，“向為數(shù)不多的瀕危病人提供” 的顯然是上一句中的sample products，即可與電源組一并植于人體內的new devices，故選D。

　　5.[B] 第2段倒數(shù)第2句But some people are already worrying…這句話體現(xiàn)了有些人已經在擔心，為為數(shù)不多的垂危病人動用巨額資金購置新型的人造心臟是否合算，而由該段最后一句可以看出作者認為這樣的做法是不明智的，因此B是答案。