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【简答题】
Thomas Edison was born in America. He invented plenty of electric appliances(电器) and people from all over the world know him. At that time, there was no electric lamp in the world. And it brought people much trouble. Young Edison decided to invent it. He didn’t know which material was suited to be a lamp filament(灯丝). He failed and failed and he spent a lot of time on it. Some of his friends asked him to stop the experiments, but he didn’t listen to them and tried his best to find the material. One afternoon, one of his friends came to visit him, he was doing his experiments in the lab when the man came in. But he only asked his friend to sit down and didn’t stop to talk with him. The man sat for a long time and Edison said nothing to him. His friend was angry with him and said, “You’ve done the experiments 1,200 times but you failed 1,200 times too!” “You’re right, my friend,” Edison went on doing his experiments and said. “But I’ve known 1,200 materials are not suited to be a lamp filament!” 小题1:Why do many people know Edison? A.Because he was very clever. B.Because he worked hard. C.Because he spent much time on his work. D.Because he invented many electric appliances. 小题2:He tried to find a kind of material which was suited to be ______. A.a lamp B.a lamp filament C.a telephone D.a light 小题3: Edison was busy with his work, so ____________. A.he asked his friend to help him B.he asked his friend to go back first C.he didn’t stop to talk with his friend D.he asked his friend to watch him working 小题4:His friend was angry because ____________. A.he couldn’t persuade Edison to give up B.Edison didn’t say hello to him C.Edison failed 1,200 times D.he didn’t think Edison was polite to him 小题5:From the passage, we learn that ___________. A.Edison was a hard-working person B.Edison never gave up C.Edison was rude to friends. D.Both A and B
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【单选题】宝宝真可爱。是男孩还是女孩?
A.
This is a lovely baby.Is it a boy or a girl?
B.
This is a lovely baby.Is he a boy or a girl?
【单选题】转速、电流双闭环调速系统在起动的恒流升速阶段中两个调节器的关系为( )。
A.
ASR 和 ACR 均饱和限幅输出
B.
ASR 不饱和, ACR 饱和限幅输出
C.
ASR 饱和限幅输出, ACR 不饱和
D.
ASR 和 ACR 均不饱和
【单选题】转速、电流双闭环调速系统在起动的恒流升速阶段中,转速调节器 ASR 和电流调节器 ACR 的作用为( )。
A.
ASR 和 ACR 均饱和限幅输出
B.
ASR 不饱和, ACR 饱的限幅输出
C.
ASR 饱和限幅输出, ACR 不饱和
D.
ASR 和 ACR 均不饱和
【判断题】项目立项前测试人员不需要提交任何工作。( )
A.
正确
B.
错误
【单选题】在字体工具框中,设置字符距离时,有以下几个选项,除了( )
A.
加宽
B.
紧缩
C.
标准
D.
对齐
【简答题】双闭环调速系统的起动过程分为三个阶段,分别是电流上升阶段、恒流升速阶段以及 阶段,在恒流升速阶段中,转速调节器是 (填饱和或不饱和)的。
【单选题】转速电流双闭环调速系统在起动的恒值电流升速阶段中,两个调节器的关系为( )。
A.
ASR 和 ACR 均饱和限幅输出
B.
ASR 不饱和, ACR 饱的限幅输出
C.
ASR 饱和限幅输出, ACR 不饱和
D.
ASR 和 ACR 均不饱和
【简答题】双闭环调速系统的起动过程分为三个阶段,分别是电流上升阶段、恒流升速阶段以及()阶段,在恒流升速阶段中,转速调节器是饱和填饱和或不饱和)的。
【判断题】转速、电流双闭环直流调速系统在起动过程的恒流升速阶段电流调节器始终是饱和的。( )
A.
正确
B.
错误
【单选题】转速、电流双闭环直流调速系统中,ASR、ACR均采用PI调节器,在电动机起动期间,保持恒定加速度升速的阶段是( )
A.
电流上升阶段
B.
恒流升速阶段
C.
转速调节阶段
D.
不确定
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