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

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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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根据短文，现在请同学们为Mr. Cao填完整他工作日的日程安排表
Mr. Cao is a teacher in a middle school．He has a lot of things to do from Monday to Friday．On Monday and Tuesday morning he has three speaking classes．On Thursday he has two writing classes in the morning and one in the afternoon．He plays ball games after class on Monday and listens to music on Tuesday afternoon．He doesn’t have classes on Wednesday or Friday．He works on the computer on Wednesday morning．He can speak a little Japanese．So he takes Japanese classes that afternoon．On Friday morning．Mr. Cao meets old friends．In the afternoon，he has a rest at home

	In the morning	In the afternoon
Monday	____	plays ball games
Tuesday	has three speaking classes	____
Wednesday	____	____
Thursday	has two writing classes	has one writing class
Friday	____	has a rest

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