直接测量电阻大小的仪表，称为欧姆表．欧姆表内部至少有______，_爱下问搜题

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问题问答题

直接测量电阻大小的仪表，称为欧姆表．欧姆表内部至少有______，______，______三大件构成．用欧姆表测伏特表的内阻时，黑表笔与伏特表的______（填“正极”或“负极”）相接．

答案

欧姆表的基本构成为：干电池、表头、调零电阻；黑表笔接内部电源的正极，用欧姆表测伏特表的内阻时，要让电流从电压表的正极进入，故黑表笔与电压表的正极相接．

故答案为：干电池，表头，调零电阻，正极

完形填空

阅读下面短文，撑握其大意，然后从1—20各题所给的四个选项（A、B、C和D）中，选出最佳选项，并在答题卡上将该项涂黑。
After the birth of my second child, I got a job at a restaurant. Having worked with an experienced 1 for a few days, I was   2 to wait tables on my own. All went 3  that first week. When Saturday night came, I was luckily 4 the tables not far from the kitchen.   5  , I still felt a little hard to carry the heavy trays (托盘)。
Before I knew it, the 6 was full of people. I moved slowly,   7 every step. I remember how 8  I was when I saw the tray stand near the tables, it looked different from the one I was 9  on. It had nice handles (手柄)，which made it 10   to move around. I was pleased with everything and began to 11 I was a natural at this job.
Then, an old man came to me and said, “Excuse me, dear, my wife and I loved __12 you work. It seems your tray stand has been very 13  to you, but we are getting ready to 14  now, and my wife needs her 15 back.”
At first his   16 did not get across. “What was he talking about!” Then I got it. I had set my trays on his wife’s orthopedic walker (助步器). I stood frozen as ice, but my face was 17 . I wanted to get into a hole and 18 .
Since then, I have learned from many mistakes such as the one I just   19  , I have learned to be more 20 and not to be too sure of myself.

小题8:angry B. calm C. sad D. happy

D．interesting

B．full of joy

判断题

在煤与瓦斯突出危险的地点工作应配戴隔离式自救器。