相关试题
【判断题】
频率的自动调节补偿是热继电器的一个功能。
【判断题】
热继电器是利用双金属片受热弯曲而推动触点动作的一种保护电器，它主要用于线路的速断保护。
【判断题】
剥线钳是用来剥削小导线头部表面绝缘层的专用工具。
【判断题】
对于异步电动机，国家标准规定3KW以下的电动机均采用三角形联结。
【判断题】
再生发电制动只用于电动机转速高于同步转速的场合。
【判断题】
电力线路敷设时严禁采用突然剪断导线的办法松线。
【判断题】
截面积较小的单股导线平接时可采用绞接法。
【判断题】
在选择导线时必须考虑线路投资，但导线截面积不能太小。
【判断题】
“止步，高压危险”的标志牌的式样是白底、红边，有红色箭头。
【判断题】
当采用安全特低电压作直接电击防护时，应选用25V及以下的安全电压。
【判断题】
RCD的选择，必须考虑用电设备和电路正常泄漏电流的影响。
【判断题】
剩余电流动作保护装置主要用于1000V以下的低压系统。
【判断题】
除独立避雷针之外，在接地电阻满足要求的前提下，防雷接地装置可以和其他接地装置共用。
【判断题】
对于容易产生静电的场所，应保持环境湿度在70%以上。
【判断题】
如果电容器运行时，检查发现温度过高，应加强通风。
【判断题】
自动空气开关具有过载、短路和欠电压保护。
【判断题】
热继电器的双金属片是由一种热膨胀系数不同的金属材料辗压而成。
【判断题】
交流接触器的额定电流，是在额定的工作条件下所决定的电流值。
【判断题】
低压配电屏是按一定的接线方案将有关低压一、二次设备组装起来，每一个主电路方案对应一个或多个辅助方案，从而简化了工程设计。
【判断题】
低压断路器是一种重要的控制和保护电器，断路器都装有灭弧装置，因此可以安全地带负荷合、分闸。
【判断题】
热继电器的双金属片弯曲的速度与电流大小有关，电流越大，速度越快，这种特性称正比时限特性。
【判断题】
摇表在使用前，无须先检查摇表是否完好，可直接对被测设备进行绝缘测量。
【判断题】
电压表在测量时，量程要大于等于被测线路电压。
推荐试题
【单选题】
- Shall we sit up here on the grass or down there near the water?___
A. I'd rather stay here if you don't mind.
B. Sorry, I don't like neither.
C. Certainly, why not？
D. Yes, we like these two places.
【单选题】
- What do you do on Sunday?___
A. I 'm a teacher.
B. I play football.
C. You are a student.
D. They clean rooms.
【单选题】
- Our class won the girls' relay race in our school's sports meeting.___
A. That's right.
B. Thanks a lot.
C. Congratulations!
D. It's a pleasure.
【单选题】
- Hi, is Mary there, please?___
A. Hold on. I'll get her.
B. No, she isn't here.
C. Yes, she lives here.
D. Yes, what do you want?
【单选题】
- I am afraid I can't return the book to you before Friday. ___
A. Don't be afraid
B. Be careful
C. Not at all
D. Take your time
【单选题】
- I really don't know how to thank you enough. ___.
A. No problem
B. Think nothing of it
C. Not at all
D. It doesn't matter
【单选题】
- Must I be home before seven? ___.
A. No, you needn't
B. No, you mustn't
C. Yes, you will
D. No, you won't
【单选题】
-I'm sorry to hear that you failed in the exam______.
A. Not at all
B. Oh, thank you.That's very kind of you
C. You are welcome
D. Yes, I'm really sorry
【单选题】
-I will,______.
A. that's all right
B. thank you
C. all right
D. not at all
【单选题】
-Hello, may I speak to Zhao Hua?_____.
A. My name is Zhao Hua
B. I'm Zhao Hua
C. This is Zhao Hua speaking
D. Zhao Hua is me
【单选题】
___This is Mr Smith speaking now.
A. Who are you
B. Who is that
C. Who are you calling
D. What do you want to say
【单选题】
- I was worried about my maths, but Mr. Brown gave me an A.___
A. Don't worry about it.
B. Congratulations! That's a difficult course.
C. Mr. Brown is very good.
D. Good luck to you！
【单选题】
-Would you go to the concert with me?___, but I'm very busy now.
A. I'd like to
B. Sure
C. No problem
D. Certainly
【单选题】
-I'll be away on a business trip. Would you mind looking at my cat?Not at all. _______.
A. I have no time
B. I'd rather not
C. You can leave
D. I'd be happy to
【单选题】
- Hi, Jim! Nice to meet you.____.
A. Certainly
B. Many thanks
C. OK
D. Nice to meet you, too
【单选题】
- Hello, may I speak to Mike?_____
A. Who are you?
B. Sorry, he isn't in.
C. Thank you very much.
D. Yes, here you are.
【单选题】
- Will you join us for lunch?____.
A. No, I won't
B. Yes, with pleasure
C. Yes, please
D. Yes, help yourself
【单选题】
- Thank you for your great dinner. I really enjoyed it._____you enjoyed it.
A. I'm so glad
B. I'm sorry
C. What a pity
D. Surprisingly
【单选题】
- I heard Susan surprised her teacher by working hard. Yes, ___
A. her teacher worked hard.
B. Susan worked hard.
C. the teacher was surprising.
D. Susan was surprised.
【单选题】
- Peter, don't step on the grass_______.
A. It doesn't matter
B. I can't do it
C. Don't worry
D. Sorry, I won't do it again
【单选题】
- How was your journey to Paris? - ____
A. It went very well.
B. I flew there.
C. I love Paris.
D. Thank you for asking.
【单选题】
- I'm sorry for being late, Mr Lt______.
A. All right
B. That's right
C. Not at all
D. Never mind
【单选题】
- Happy birthday to you! ___!
A. Happy birthday to you
B. I'm very glad
C. That's all right
D. Thank you
【单选题】
- Do you like country music?___.
A. Yes, I like basketball a lot
B. It's far too crowded
C. Yes, I'm crazy about it
D. Oh, it's funny
【单选题】
- Have a cup of tea, ____? Thanks a lot.
A. don't you
B. haven't you
C. shall we
D. will you
【单选题】
- Thank God．It's Friday again．A nice weekend!___.
A. Me too
B. Yes，I'll be free then
C. That's all right
D. The same to you
【单选题】
— Write to me when you get home. OK, I ______.
A. must
B. should
C. will
D. can
【单选题】
Tom is so talkative. I’m sure you'll soon get tired ___ him.
A. of
B. with
C. at
D. on
【单选题】
I don't know ____ to deal with such matter.
A. what
B. how
C. which
D. /
【单选题】
___ is your girl friend like? She is very kind and good-looking.
A. How
B. What
C. Which
D. Who
【单选题】
He ___ driving me home, even though I told him I lived nearby.
A. insisted on
B. insisted at
C. insisted that
D. insisted in
【单选题】
We came finally ___the conclusion that she has been telling lies all the time.
A. of
B. into
C. to
D. at
【单选题】
I won’t make the___mistake next time.
A. like
B. same
C. near
D. similar
【单选题】
He ___lives in the house where he was born.
A. already
B. yet
C. still
D. ever
【单选题】
I am not used to speaking ___ public.
【单选题】
I didn’t know what to do, but then an idea suddenly ___to me.
A. appeared
B. happened
C. occurred
D. emerged
【单选题】
Measles （麻疹） ___ a long time to get over.
A. spend
B. spends
C. take
D. takes
【单选题】
A pair of spectacles ___ what I need at the moment.
A. is
B. are
C. has
D. have
【单选题】
— Five days ___ too long for me to wait.
A. was
B. were
C. is
D. are
【单选题】
You had better ___ a doctor as soon as possible.
A. seeing
B. saw
C. see
D. seen
