问题 单项选择题 A1型题

确定化学物对人类致癌性最有价值的方法是()

A.原癌基因激活试验

B.肿瘤抑制基因灭活试验

C.外周血淋巴细胞染色体畸变试验

D.姐妹染色体交换试验(SCE.

E.肿瘤流行病学调查

答案

参考答案:E

解析:本题考核确定人致癌物的证据。确定人类致癌物证据为:①流行病学调查结果能够重复;②有剂量一反应关系;③有动物致癌试验阳性结果支持。因此确定人致癌物最重要的是可重复的流行病学调查的阳性结果。本题正确答案是E。备选答案A、B只是说明致癌的机制或作为生物学标志,C和D是致突变试验,只作为筛检致癌性,故都不正确。

名词解释
填空题

For centuries people have been fighting over whether governments should allow trade between countries. There have been, and probably always will be, (1) to the argument. Some people argue that just (2) is best for both the country and the world. Others argue that trade with other countries (3) for some people to make a good living. Both sides are at least (4) .
International trade matters a lot. Its effects on (5) are enormous. Imagine a world in which your country (6) at all with other countries. Imagine what kind of job you would be (7) and what goods you could buy or not buy in such a world.
For the United States, for example, start by imagining that it lived without its (8) a year in imported oil, and cut back on its (9) because the remaining domestic oil and other energy sources were (10) . Producers and consumers in other parts of the economy would (11) if they were suddenly stripped of foreign-made goods like CD players and clothing. On the (12) side, suppose that Boeing could sell airplanes, and farmers could sell their crops, (13) the United States, and that U. S. universities could admit only (14) . In each case there are people who gain and people who lose from (15) international trade. In any case, less or more international trade will have (16) on your career as well as your life.
For years, American companies are often faced with the choice of buying (17) , which are expensive, and foreign-made goods, which are cheap. If the company buys American goods, it may (18) taxpayers by failing to keep prices low. But if it buys foreign goods, it may (19) the jobs of American workers. Recently, Congress has passed a law compelling American companies with government contracts to (20) domestic goods and services.

For centuries people have been fighting over whether governments should allow trade between countries. There have been, and probably always will be, (1) to the argument. Some people argue that just (2) is best for both the country and the world. Others argue that trade with other countries (3) for some people to make a good living. Both sides are at least (4) .
International trade matters a lot. Its effects on (5) are enormous. Imagine a world in which your country (6) at all with other countries. Imagine what kind of job you would be (7) and what goods you could buy or not buy in such a world.
For the United States, for example, start by imagining that it lived without its (8) a year in imported oil, and cut back on its (9) because the remaining domestic oil and other energy sources were (10) . Producers and consumers in other parts of the economy would (11) if they were suddenly stripped of foreign-made goods like CD players and clothing. On the (12) side, suppose that Boeing could sell airplanes, and farmers could sell their crops, (13) the United States, and that U. S. universities could admit only (14) . In each case there are people who gain and people who lose from (15) international trade. In any case, less or more international trade will have (16) on your career as well as your life.
For years, American companies are often faced with the choice of buying (17) , which are expensive, and foreign-made goods, which are cheap. If the company buys American goods, it may (18) taxpayers by failing to keep prices low. But if it buys foreign goods, it may (19) the jobs of American workers. Recently, Congress has passed a law compelling American companies with government contracts to (20) domestic goods and services.