问题
单项选择题
九管发动机中，多增加的三个二极管的作用是（）。
A.提高发电机的功率
B.引出中性点接线柱
C.用来控制充电指示灯
D.用来调节输出电压，使输出电压保持恒定
答案
参考答案：C
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九管发动机中，多增加的三个二极管的作用是（）。
A.提高发电机的功率
B.引出中性点接线柱
C.用来控制充电指示灯
D.用来调节输出电压，使输出电压保持恒定
参考答案：C
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| Ten-year-old Johnny was one of the laziest boys in his class. His homework was always 1 and it was usually wrong. He only did half the number of math problems 2 the other children did and in his compositions he 3 half the number of words. And usually the words were 4 spelled because he was too lazy to use a 5 . One day his class went on a bus trip. The 6 did not want to take Johnny with them. But there was no one to look after Johnny at the school so she had to take 7 . "Now, children," the teacher said, "On our bus trip we will 8 old buildings, some beautiful countryside, and many other things. I want you to write about 9 interesting you see on the trip." The bus trip 10 . The children looked out of the windows at all the interesting things. They took notes 11 their notebooks. The teacher was very 12 with them. Then she saw Johnny 13 on the floor of the bus and went up to him. "Are you 14 ?" she asked him. "No." he said. "Then 15 are you lying on the floor?" "If I can't see anything," he said, "I can't write about it, can I?" | ||||
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