题干

如图所示,闭合开关后,无论如何移动滑片P,小灯泡始终不亮,已知导线及各处连接完好.为查找故障,开关闭合后,用电压表测得三次两接线柱间电压如表所示,则(   )

两接线柱

电压表示数

A和B

3V

A和D

3V

A和F

0V

A:只可能是小灯泡发生短路故障

B:只可能是小灯泡发生断路故障

C:还需测得H、G间电压,才能判定滑动变阻器是否发生断路故障

D:还需测得G、B间电压,才能判定滑动变阻器是否发生断路故障

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答案(点此获取答案解析)

D

同类题2

阅读下面短文,从每小题所给的A、B、C、D四个选项中选出最佳选项。


    Some people think that success is only for those with talent or those who grow up in the right family, and others believe that success mostly comes down to luck. I'm not going to say luck, talent, and circumstances don't come into play because they do. Some people are born into the right family while others are born with great intelligence, and that's just the reality of how life is.

    However, to succeed in life, one first needs to set a goal and then make it more practical. And, besides that, in order to get really good at something, one needs to spend at least 10,000 hours studying and practising. To become great at certain things, it'll require even more time, which most people won't put in.

    This is a big reason why many successful people advise you to do something you love. If you don't enjoy what you do, it is going to feel like unbearable pain and will likely make you give up before you ever become good at it.

    When you see people exhibiting some great skills or having achieved great success, you know that they have put in a huge part of their life to get there. It's sometimes easy to think they got lucky or they were born with some unusual talent, but thinking that way does you no good, and there's a huge chance that you're wrong anyway.

    No matter what you do, if you want to become great at it, you need to work day in and day out, almost to the point of addiction, and over a long period of time. If you're not willing to put in the time and work, don't expect to receive any rewards. Hard work won't guarantee you the level of success you may want, but it will guarantee that you will become really good at whatever it is you put all that work into.