【填空题】
105.利用晶闸管电路把直流电转变成交流电,这种对应于整流的逆向过程,叫做____。___
查看试卷，进入试卷练习
微信扫一扫，开始刷题
答案
逆变
解析
暂无解析
相关试题
推荐试题
【单选题】
6. Susan, why are you still here? They are all ready to start.
Im sorry, but I _________ when to start.
A. dont tell B. wasnt told C. didnt tell D. havent told
A. A
B. B
C. C
D. D
【单选题】
7.—Why dont you choose the red tie?
—For me, it doesn’t _____ my shirt very well．
A. fix B. accept C. compare D. match
A. A
B. B
C. C
D. D
【单选题】
8. — Could you tell me ______? I must find him．
— Sorry．I don’t know．But he was here just now．
A. where Tom was B. where Tom is
C. where has Tom gone D. where can I find Tom
A. A
B. B
C. C
D. D
【单选题】
9. —What did Mr Green say to you?
— What a heavy rain! How did you come here? He asked________.
A. at all B. in fact C. in surprise D. as a result
A. A
B. B
C. C
D. D
【单选题】
10. I often see Tom on the playground．When I passed the playground yesterday, I saw him ．
A. play; playing B. to play; play C. playing; to play D. playing; play
A. A
B. B
C. C
D. D
【单选题】
11. — Mum, could I have ____________ to drink?
— Oh, dear．You can only drink some water．There is _________ in the kitchen．
A. anything; else something B. anything; something else
C. something; else nothing D. something; nothing else
A. A
B. B
C. C
D. D
【单选题】
12. We all know that learning a foreign language _______ time and effort.
A. requires B. reduces C. removes D. repeats
A. A
B. B
C. C
D. D
【单选题】
13. Her son __________ Coke, but now he __________ milk．
A. is used to drinking; used to drink B. used to drink; uses to drink
C. used to drink; is used to drinking D. is used to drink; is drinking
A. A
B. B
C. C
D. D
【单选题】
14. I don’t know the teacher is talking with Miss Wang．
A. what B. whom C. who D. which
A. A
B. B
C. C
D. D
【单选题】
15.Millie does __________ that many people are thankful to her．
A. such an important and helpful job B. so important and helpful work
C. a very important and helpful job D. such an important and helpful work
A. A
B. B
C. C
D. D
【单选题】
16. I think eating more vegetables is good _______ our health.
—Yes, I agree _______ you.
A. at, to B. for, with C. to, to D. for, to
A. A
B. B
C. C
D. D
【单选题】
17. I often go on holiday with my parents _____ summer.
A. in B. at C. on D. of
A. A
B. B
C. C
D. D
【单选题】
18. I called you at 4:00 yesterday afternoon, but nobody answered.
Sorry, I ______ with my friends at that time.
A. had swum B. swam C. would swim D. was swimming
A. A
B. B
C. C
D. D
【单选题】
19.––Who is on the playground? ---__________．
A. Never B. None C. No one D. A lot
A. A
B. B
C. C
D. D
【单选题】
20. The schoolboy ______ a blind man cross the street yesterday.
A. helps B. helped C. will help D. has helped
A. A
B. B
C. C
D. D
【单选题】
21. —The 2010 World Expo which will last 184 days will be held in Shanghai on May 1st.
—________exciting news! We shall try our best to support it.
A. How B. How an C. What D. What an
A. A
B. B
C. C
D. D
【单选题】
22. They preferred ______ in bed rather than _____ horses．
A. to lie; to ride B. lying; riding C. lying; ride D. to lie; ride
A. A
B. B
C. C
D. D
【单选题】
23. —What was Jim wearing at the party?
— Nothing _______. He was in his usual shirt and jeans.
A. special B. simple C. important D. interesting
A. A
B. B
C. C
D. D
【单选题】
24. The 2016 Olympic Games ________ in Brazil. Would you like to go there?
Maybe, if possible.
A. are held B. will be held C. were held D. have been held
A. A
B. B
C. C
D. D
【单选题】
25. — David, look at the man in white over there．Can you tell me _______ ?
—He is a doctor．
A. who is he B. who he is C．what does he do D. what he does
A. A
B. B
C. C
D. D
【单选题】
( ) 26.With help from a Mr. H, you can__________.
A. stop wearing your watch B. get new books and objects
C. finish your homework on time D. know when parents or teachers are near
A. A
B. B
C. C
D. D
【单选题】
( ) 27. A PENGO WATCH CONTROL can help you to ______________.
A. repair your TV B. put away your books and objects
C. become a James Bond D. get a daily weather report
A. A
B. B
C. C
D. D
【单选题】
( ) 28. You can get your Mr. H for___________.
A. $299 B. $499 C. $199 D. $99
A. A
B. B
C. C
D. D
【单选题】
( ) 29. When was canned food invented?
A. In 1870. B. In 1810. C. In 1902. D. In 1926.
A. A
B. B
C. C
D. D
【单选题】
( ) 30. After the trip to the Arctic, Clarence Birdseye invented ____________.
A. canned food B. can openers
C. frozen food D. air conditioning
A. A
B. B
C. C
D. D
【单选题】
( ) 31. Changes in weather _____________ in Willis Carrier's company.
A. helped to keep food B. made rooms comfortable
C. caused health problems D. hurt printing paper
A. A
B. B
C. C
D. D
【单选题】
( ) 32. According to the passage, which of the following may lead to inventions?
A. People's needs. B. Public support.
C. Modern technology. D. Practical suggestions.
A. A
B. B
C. C
D. D
【单选题】
( ) 33. What is the writer's main purpose（目的）in writing this passage？
A．To tell the readers his life story．
B．To tell people what kind of person his father was．
C．To tell the readers what present he got from his father．
D． To let people know how poor he was．
A. A
B. B
C. C
D. D
【单选题】
( ) 34. Why did the father not ask his son not to do this and do that？
A．Because he felt quite confident of his son．
B．Because he was born from a poor family．
C．Because he was a man of few words．
D．Because he didn't want to be much too strict with his son．
A. A
B. B
C. C
D. D
【单选题】
( ) 35. What would someone learn from this passage？
A．How to live by oneself． B．How to stand on one's own feet．
C．What a good father should do． D．What the self-important is like．
A. A
B. B
C. C
D. D
【单选题】
( ) 36. What may be the proper Chinese for the underlined part in the passage？
A．闲暇时光 B．学费 C．精神空虚 D．经济不足
A. A
B. B
C. C
D. D
【单选题】
( ) 37. The Chinese Yellow Sea Wetlands are in the _______ of China．
A．south B．east C．west D．north
A. A
B. B
C. C
D. D
【单选题】
( ) 38. Usually the weather in the wetlands is _______．
A．hot B．pleasant C．cold D．dry
A. A
B. B
C. C
D. D
【单选题】
( ) 39. The World Wetlands Day is on _______．
A．February 2 B．June 25 C．April 22 D．March
A. A
B. B
C. C
D. D
【单选题】
( ) 40. We must protect wetlands because _______．
A．they are home for wildlife B．they can prevent flood
C．they can offer food to the animals and birds D．all of the above
A. A
B. B
C. C
D. D
【单选题】
) 1. —Is it far from here to the bank?
—Not very, only________．
A. 20 minute’s walk B. 20 minutes walk
C. 20 minutes’ walk D. 20 minutes’ walks
A. A
B. B
C. C
D. D
【单选题】
2. — After discussing, the students ________ some good ideas to work on the project.
— Thats great!
A. put up B. set up C. caught up with D. came up with
A. A
B. B
C. C
D. D
【单选题】
3. Yesterday Tommy walked past my table and ______ my bowls and dishes.
He should be careful next time.
A. knocked off B. took off C. showed off D. turned off
A. A
B. B
C. C
D. D
【单选题】
4.We don’t have enough nurses to look after patients．At least ___ nurses are needed．
A. ten another B. more ten C. another ten D. other ten
A. A
B. B
C. C
D. D
【单选题】
5. — Zhao Rui, it’s said that many famous singers will come to Yangzhou on April 18th. How about watching the evening show there?
—________! Let’s ask Huang Tao to go with us.
A. Best wishes B. Sounds great C. Good luck D. That’s OK
A. A
B. B
C. C
D. D
