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.
增大，如果滑动前达到饱和电流，那么滑动后电流不再增大，C错误；若滑动头左滑
，是反向电压，只要不超过反向遏制电压，就有光电流，故D正确；