【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
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答案
C
解析
C
相关试题
【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
【单选题】
6.—Hello! This is Henry Speaking.I’d like to speak to your father. —Sorry, he has Shanghai. A. been in B. been to C. come to D. gone to
A. A
B. B
C. C
D. D
【单选题】
7. — It’s difficult for the village children to cross the river for school. — I think a bridge ______ over the river. A. was built B. is being built C. has been built D. should be built
A. A
B. B
C. C
D. D
【单选题】
8. —Where would you like to go, Jinan or Qufu? — .I only want to go to Qingdao. A. Each B. Either C. Neither D. All
A. A
B. B
C. C
D. D
【单选题】
9 — The documentary A Bite Of China II is quite popular around China recently. How do you like it? ______. A. I think so B. Pretty good C. Its my pleasure D. All right
A. A
B. B
C. C
D. D
【单选题】
10. There are three English-books on the shelf, but ______ of them is mine. A. both B. neither C.all D. none
A. A
B. B
C. C
D. D
【单选题】
11. When the parents arrived at the hall, the students _______ their projects. A. have finish B. finished C. had finished D. are finishing
A. A
B. B
C. C
D. D
【单选题】
12. This week, the _______ seems to change every day: one day is hot; the next day is cold. A. time B. weather C. season D. way
A. A
B. B
C. C
D. D
【单选题】
13. He never does his work _______ Mary.    A. as careful as B. so careful as C. carefully as D. as carefully
A. A
B. B
C. C
D. D
【单选题】
14. — Can he jump high? — Yes, he ______. He is a good high jumper. A. must B. need C. can D. shall
A. A
B. B
C. C
D. D
【单选题】
15. The shop _____ at 8:00 a.m.and it ________ for ten hours every day. A. is open; has opened B. is opened; opens C. opens; is open D. opened; opens
A. A
B. B
C. C
D. D
【单选题】
16. —Excuse me, may I use your bicycle? ______ is broken. Certainly. But remember to return it before lunch. A. Mine B. Me C. Myself D. I
A. A
B. B
C. C
D. D
【单选题】
17. Simon, what do I need to take for the hiking? Youd better ________ more water than usual. Its hot today. A. to take B. taking C. take D. took
A. A
B. B
C. C
D. D
【单选题】
18. Helen ______ to a language school when she was seven. A. sent B. is sent C. will send D. was sent
A. A
B. B
C. C
D. D
【单选题】
19. — Is this park youve visited recently? — Yes, it's the most beautiful one Ive ever visited before. A. that B. the one C. which D. the one which
A. A
B. B
C. C
D. D
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【单选题】
垂直穿过磁场中某一截面的磁力线条数叫作___。
A. 磁通或磁通量
B. 磁感应强度
C. 磁导率
D. 磁场强度
【单选题】
单位面积上垂直穿过的磁力线数叫作___。
A. 磁通或磁通量
B. 磁导率
C. 磁感应强度
D. 磁场强度
【单选题】
磁场内各点的磁感应强度大小相等、方向相同,则称为___。
A. 均匀磁场
B. 匀速磁场
C. 恒定磁场
D. 交变磁场
【单选题】
铁磁材料在磁化过程中,当外加磁场H不断增加,而测得的磁场强度几乎不变的性质称为___。
A. 磁潜性
B. 剩磁性
C. 高导磁性
D. 磁饱和性
【单选题】
铁磁性质在反复磁化过程中的B-H关系是___。
A. 起始磁化曲线
B. 磁滞回线
C. 基本磁化曲线
D. 局部磁滞问线
【单选题】
当线圈中的磁通减小时,感应电流产生的磁通与原磁通方向___。
A. 正比
B. 反比
C. 相反
D. 相同
【单选题】
磁感应强度B与磁场强度H的关系为___。
A. H=μB
B. B=μH
C. H=μ0B
D. B==μ0B
【单选题】
穿越线圈回路的磁通发生变化时,线圈两端就产生___。
A. 电磁感应
B. 感应电动势
C. 磁场
D. 电磁感应强度
【单选题】
正弦量有效值与最大值之间的关系,正确的是___。
A. E=Em/根号2
B. U=Um/根号2
C. Iav=2π×5
D. Eav=Em/2
【单选题】
已知工频正弦电压有效值和初始值为380V,则该电压的瞬时值表达式为___。
A. u=380sin314tV
B. u=537sin(314t+45°)V
C. u=380sin(3l4t+90°)V
D. u=380sin(314t+45°)V
【单选题】
在正弦交流电路中,电路的功率因数取决于___。
A. 电路外加电压的大小
B. 电路各元件参数及电源频率
C. 电路的连接形式
D. 电路的电流
【单选题】
提高供电线路的功率因数,下列说法正确的是___。
A. 减少了用电设备中无用的无功功率
B. 可以节省电能
C. 减少了用电设备的有功功率,提高了电源设备的容量
D. 可提高电源设备的利用率并减少输电线路中的功率损耗
【单选题】
三相对称电路的线电压比对应相电压___。
A. 超前30°
B. 超前60°
C. 滞后30°
D. 滞后60°
【单选题】
三相电动势到达最大的顺序是不同的,这种达到最大值的先后次序,称为三相电源的相序,相序为U-V-W-0,称为___。
A. 正序
B. 负序
C. 逆序
D. 相序
【单选题】
有一台三相交流电动机,每相绕组的额定电压为220V,对称三相电源电压为380V,则电动机的三相绕组应采用的联结方式是___。
A. 星形联结,有中线
B. 星形联结,无中线
C. 三角形联结
D. A、B均可
【单选题】
一对称三相负载,三角形联结时的有功功率等于星形联结时的___倍。
A. 3
B. 根号3
C. 根号2
D. 1
【单选题】
对称三相电路负载三角形联结,电源线电压为380V负载复阻抗为Z=(8+6j)Q则线电流为___。
A. 38A
B. 22A
C. 54A
D. 66A
【单选题】
将变压器的一次绕组接交流电源,二次绕组___,这种运行方式称为变压器空载运行。
A. 短路
B. 开路
C. 接负载
D. 通路
【单选题】
将变压器的一次绕组接交流电源,二次绕组开路,这种运行方式称为变压器___运行。
A. 空载
B. 过载
C. 满载
D. 负载
【单选题】
变压器的基本作用是在交流电路中变电压、变电流、___、变相位和电气隔
A. 变磁通
B. 变频率
C. 变功率
D. 变阻抗
【单选题】
变压器的器身主要由铁芯和___两部分组成。
A. 绕组
B. 转子
C. 定子
D. 磁通
【单选题】
变压器的绕组可以分为同心式和___两大类。
A. 同步式
B. 交叠式
C. 壳式
D. 芯式
【单选题】
三相异步电动机具有结构简单、工作可靠、重量轻、___等优点。
A. 调速性能好
B. 价格低
C. 功率因数高
D. 交直流两用
【单选题】
三相异步电动机的优点是___。
A. 调速性能差
B. 交直流两用
C. 功率因数高
D. 结构简单
【单选题】
三相异步电动机的缺点是___。
A. 结构简单
B. 重量轻
C. 调速性能差
D. 转速低
【单选题】
三相异步电动机的定子由___、定子铁芯、定子绕组、端盖、接线盒等组成。
A. 电刷
B. 机座
C. 换向器
D. 转子
【单选题】
三相异步电动机的转子由___、转子绕组、风扇、转轴等组成。
A. 转子铁芯
B. 机座
C. 端盖
D. 电刷
【单选题】
电流流过电动机时,电动机将电能转换成___。
A. 机械能
B. 热能
C. 光能
D. 其他形式的能
【单选题】
某异步电动机的额定功率是10kW,额定转速是955r/min,则该电动机的额定转矩是___N·m。
A. 100
B. 10
C. 955
D. 95.5
【单选题】
交流异步电动机的电磁转矩与___关系。
A. 定子电压成反比
B. 定子电压的平方成反比
C. 定子电压成正比
D. 定子电压的平方成正比
【单选题】
交流接触器的文字符号是___
A. 05
B. 50
C. 5A
D. KM
【单选题】
热继电器的作用是___。
A. 短路保护
B. 过载保护
C. 失压保护
D. 零压保护
【单选题】
三相刀开关的作用是接通和断开___电路。
A. 大电流
B. 负载
C. 电压或小电流
D. 三相电动机
【单选题】
三相异步电动机的启停控制线路由电源开关、熔断器、___、热继电器、按钮等组成。
A. 时间继电器
B. 速度继电器
C. 交流接触器
D. 漏电保护器
【单选题】
维修电工以___、安装接线图和平面布置图最为重要。
A. 电气原理图
B. 电气设备图
C. 电气安装图
D. 电气组装图
【单选题】
读图的基本步骤有看图样说明,___,看安装接线图。
A. 看主电路
B. 看电路图
C. 看辅助电路
D. 看交流电路
【单选题】
双极型半导体元件是___。
A. 二极管
B. 三极管
C. 场效应管
D. 稳压管
【单选题】
用万用表检测某二极管时,发现其正、反电阻均约等于1kΩ,说明该二极管___。
A. 已经击穿
B. 完好状态
C. 内部老化不通
D. 无法判断
【单选题】
当二极管外加的正向电压超过死区电压时,电流随电压增加而迅速___
A. 增加
B. 减小
C. 截止
D. 饱和反向
【单选题】
三极管是由三层半导体材料组成的。有三个区域,中间的一层为___。
A. 基区
B. 栅区
C. 集电区
D. 发射区