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问题 选择题

如图所示的电路中，电源两端的电压保持不变．闭合开关S，将滑动变阻器的滑片P向右移动，下列说法正确的是：

A．电流表A的示数变小，电压表V1的示数变大

B．电流表A的示数变小，电压表V2的示数变大

C．电压Vl与电压表V2的示数之和保持不变

D．电压表V2与电流表A的示数之比保持不变

答案

答案：B

题目分析：在此电路中，两个电阻是串联的，电压表V1测量的是电源电压，电压表V2串联的是滑动变阻器两端的电压，闭合开关S，将滑动变阻器的滑片P向右移动，滑动变阻器的电阻变大，电路中的电流变小，电压表V2的示数变大，电压表V1的示数不变。

A．电流表A的示数变小，电压表V1的示数变大 不合题意；

B．电流表A的示数变小，电压表V2的示数变大 符合题意；

C．电压Vl与电压表V2的示数之和保持不变 不合题意；

D．电压表V2与电流表A的示数之比保持不变 不合题意；

故选B。

点评：在电表示数变化的问题时，先认清电路的连接情况，在根据滑动变阻器的阻值变化分析电压表和电流表的示数变化情况。

多项选择题

间接接触能感染的传染病有（）。

A.伤寒

B.淋病

C.痢疾

D.狂犬病

E.艾滋病
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THE CHARM OF CHARITY
A poor young man lost his job and had no one to help him. Helpless, homeless and hopeless, he decided to commit suicide. He   36  all the coins he had with him and bought a ripe banana wrapped in an old newspaper. He opened the packet and started to eat his last food   37  an old beggar approached him. With trembling lips, the beggar told him that he hadn’t had anything to eat for several days and was too weak to walk. The young man felt   38 . So he didn’t eat the banana.   39 , he gave the banana to the beggar. The beggar ate it with great joy and   40__  him. While leaving, the beggar gave him a very old coin, saying, “Thank you very much. You gave me everything you had. Kindly accept this coin as my gift   41  your kindness.”
After the old man left, he   42  glanced at the piece of paper used to wrap the fruit. There he saw a（n）  43  from an agency dealing with old coins. Anyone   44  old coins was invited to visit the agency and receive suitable price for their old coins on the spot. Out of simple   45 , he carried the coin to the agency after   46  it by phone. He showed the coin gifted by the beggar. The person who   47  the agency stared at it and told him in excitement, “What a   __48  ! It is very   49  and several centuries old. It is worth a（n）  50  !” Jumping with joy on receiving the   51  amount of money, he searched everywhere to find the old man who gifted him the coin. He wanted to   52  his joy and the money with the beggar. But he could not find him anywhere. Since then, he started a new life with renewed   53  and enthusiasm about the future.
Kindness will be   54 . It always comes back! As William Wordsworth wrote,“ The best part of a good life is the little, nameless, unremembered acts of   55  and love.”
小题1:
A．collectB．spreadC．spottedD．donated
小题2:
A．whileB．whenC．before D．until
小题3:
A．worriedB．nervousC．pityD．guilty
小题4:
A．Still B．ThusC．BesidesD．Instead
小题5:
A．scoldedB．admiredC．respectedD．thanked
小题6:
A．in search forB．in terms ofC．in return forD．in favor of
小题7:
A．carelesslyB．purposelyC．ImmediatelyD．normally
小题8:
A．suggestionB．advertisementC．appealD．requirement
小题9:
A．possessingB．seeingC．orderingD．deserving
小题10:
A．distrustB．curiosityC．wonderD．hobby
小题11:
A．replyingB．repeatingC．contactingD．begging
小题12:
A．charged B．consistedC．attendedD．managed
小题13:
A．shameB．prizeC．surpriseD．pleasure
小题14:
A．privateB．freshC．rareD．casual
小题15:
A．valueB．fortuneC．wealth D．effort
小题16:
A．unexpectedB．unluckyC．unlimitedD．unnoticed
小题17:
A．hideB．shareC．coverD．spare
小题18:
A．wisdomB．chanceC．hopeD．luck
小题19:
A．changedB．damaged C．lostD．rewarded
小题20:
A．courage B．promiseC．memoryD．kindness
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