一根粗细均匀的金属丝,电阻为R,把它截成等长的几段,再把这几段并

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问题选择题

一根粗细均匀的金属丝,电阻为R,把它截成等长的几段,再把这几段并联起来,等温度一定时. 导体的电阻与导体的长度L成正比,与导体的横截面积S成反比.用公式表示为,ρ为正比例常数,则并联后的电阻应为[ ]

A.R

B.nR

答案

答案：D

句型转换

句型转换，每空一词，含缩略词。

1. Michael felt terrible when he was ill.(对划线部分提问)

__________ did Michael __________ when he was ill?

2. The boy looked worried because he lost his ticket to the movie.(对划线部分提问)

__________ did the boy __________ worried?

3. He was too tired to go on any longer.(改为同义句)

He was ________ tired ________ he couldn't go on any longer.

4. Steve can't speak Chinese. I think.(将两句合并为一句)

I __________ think Steve __________ speak Chinese.

5. How interesting the book is! (改为同义句)

__________ __________ interesting book it is!

6. The gold ring cost Ms Howe RMB 120. (同义句)

Ms Howe ____________ the gold ring ____________ RMB 120.

7. You had better design your own uniforms.(改为否定句)

You ________ ________ ________ design your own uniforms.

单项选择题

《特种设备作业人员考核规则》规定，持《特种设备作业人员证》的人员，应当在期满3个月前，向（）提出复审申请，也可以将复审申请材料提交考试机构，由考试机构统一办理。

A、政府部门

B、质检部门

C、发证部门

D、用人单位