题干

如图所示,电源电动势E=3V,小灯泡L标有“2V  0.4W”,开关S接1,当滑动变阻器调到R=4Ω时,小灯泡L正常发光;现将开关S接2,小灯泡L和电动机M均正常工作,则(  )

A:电源的内阻为1Ω

B:电动机的内阻为2Ω

C:电动机正常工作的电压为1 V

D:电源的效率为80%

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A

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    Some people think the government should move the big companies and factories in cities to the countryside. To what extent do you agree?

    Due to the increased urbanization, there appears a bunch of heated social problems. Some people have noticed that there are many big companies and factories in the city and they believe that moving those big companies and factories into countryside could be a good way to solve many of the city problems, such as traffic issues and housing problems. However, I hold an opposite opinion to them and I will explain it as below.

    Cities have much more advantages than countryside. There are more cinemas, restaurants and shopping malls in cities, let alone better education and health care. Living in cities makes life more convenient and enjoyable. Thus not everyone is willing to move to countryside in spite of their companies' moving. They have got cars, which transfers them easily between work and home. Therefore, the pressure of traffic will not be released due to such solution. As for the available empty places spared by the big companies, the newest small companies will take good care of them—with the realization of the benefits that running a business in cities will bring to them. In other words, situation of housing will not be improved much.

    Besides, there will be more problems if big companies and factories move out. Where there are big companies and factories, there will be cities sooner or later. Consequently, countryside is to be disappearing. What's more, industrial pollution is not an easily mended problem.

    In conclusion, moving big companies and factories out of cities is never a final solution. It tackles(解决) no problem but causes lots of them. Just imagine. The traffic is still terrible, and there is no more scenic countryside. We should look into other ways to solve the problems.