题干

 2013年12月14日,我国“嫦娥三号”成功着陆在月球虹湾区,15日“嫦娥三号”着陆器与“玉兔号”月球车分离,月球车顺利驶抵月球表面,关于月球车的说法正确的是(  )

A:月球车由运动变为静止,不需要力的作用

B:月球车的车轮做得较宽,是为了减小压力

C:月球车在月球表面运动时,牵引力与阻力一定是一对平衡力

D:看到月球车停在月球表面上静止不动,是以月球为参照物

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答案(点此获取答案解析)

D

同类题4

阅读下面短文,从A、B、C、D四个选项中选出最佳选项。

    The government in China ended his one-child policy and let families have two children instead in 2015.

    A Chinese Communist Party statement gave a number of reasons for the change in policy. The statement said the change is meant to balance population development, stop a falling birth rate(出生率)and strengthen the country's labor force(劳动力). China, with the largest population in the world, started the one-child policy in 1980. But the government allowed only a small number of couples to have two children. For example, some families in the countryside could have two children, if the first-born is a girl.

    In 2013, the Chinese government gave other couples a chance to have two children if one of them was an only child.

Jiang Quanbao, a teacher and population expert, explained how Chinese families react(反应) to the newest policy. "Too many young people in the cities are no longer interested in having a second child," he said. "People in the countryside are more interested. But some of them are already allowed to have two children." At the end of 2014, China had a population of 1.37 billion people. A total of 800 million of them have jobs. But the labor market need of labor by the year 2050. With the two-child policy, an increase in births can solve this problem.

    Boys and girls, what do you think of the two-child policy? Do you want to have a new-born brother or sister?