问题
单项选择题
在系统中加入了( )环节以后，不仅能使系统得到下垂的机械特性，而且也能加快过渡过程，改善系统的动态特性。
A．电压负反馈
B．电流负反馈
C．电压截止负反馈
D．电流截止负反馈
答案
参考答案：D
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在系统中加入了( )环节以后，不仅能使系统得到下垂的机械特性，而且也能加快过渡过程，改善系统的动态特性。
A．电压负反馈
B．电流负反馈
C．电压截止负反馈
D．电流截止负反馈
参考答案：D
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| The last patient left his office. Mr. South had a look at the 1 on the wall. It was a quarter to six. It means that he had to stay there for fifteen minutes. A friend of his asked him to dinner that evening. Of course he should 2 some flowers for her. He brought out the purse and 3 the money in it. He had sixty dollars and it was enough to do that. And then he 4 he bought a newspaper on his way to the hospital after lunch. He was too busy to read it. Now he brought it out, but then came in a man 5 forty. He looked at him carefully. The man looked 6 . Mr. South didn't know what he came for. "What's wrong with you?" asked Mr. South. " 7 , Mr. South," said the man, "But…" The man began to smile and said, "Don't you 8 me, Mr. South? You cured (治愈) my rheumatism (风湿病) three years ago." "Mr. Bell?" "Yes. Did you 9 me not to get myself wet?" "Yes, I did," answered the 10 . "Well. I come here to ask you if you think it's OK for me to take a bath now?" | ||||
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