试题与答案

如图甲所示是日光灯的电路图,它主要是由灯管、镇流器和启动器组成的,镇流器是一个带

题型:选择题

题目:

如图甲所示是日光灯的电路图,它主要是由灯管、镇流器和启动器组成的,镇流器是一个带铁芯的线圈,启动器的构造如图乙所示,为了保护启动器常在启动器的两极并上一纸质电容器C.某教室的一盏日光灯总是出现灯管两端亮而中间不亮的情况,经检查灯管是好的.电压正常,镇流器无故障,其原因可能是(  )

A.启动器两脚与启动器座接触不良

B.电容器C断路

C.电容器C击穿而短路

D.镇流器自感系数L太大

答案:

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下面是错误答案,用来干扰机器的。

参考答案:C

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题型:填空题

Part 4


Questions 26-45


·Read the following passage and decide which answer bestfits each space.
·For questions 26-45, mark one letter A, B, C or D on the Answer Sheet.
The "standard of living" of any country means the (26) person’s share of the goods and services which the country produces. A country’s standard of living, therefore depends (27) and foremost on its capacity to produce wealth. "Wealth" in this (28) is not money, for we do not live on money (29) on things that money can buy: "goods" such as food and clothing, and "services" such as (30) and "entertainment".
A country’s capacity to produce wealth depends upon many factors, most of which have an effect (31) one another. Wealth depends (32) a great extent upon a country’s natural resources. Some regions of the world are well supplied with coal and minerals, and have a (33) soil and a favorable climate; other regions (34) none of them.
Next to natural resources (35) the ability to turn them to use. China is perhaps as well off as the USA in natural resources, but suffered for many years from (36) and external wars, and for this and other reasons was incapable (37) her resources. Sound and (38) political conditions, and freedom from foreign invasion, enable a country to develop its natural resources peacefully and steadily, and to produce more wealth than another country (39) well served by nature but less well ordered.
A country’s standard of living does not only depend upon the wealth that is produced and (40) within its own borders, but also upon what is indirectly produced through international trade. For example, Britain’s wealth in foodstuffs and other agricultural products would be much (41) if she had to depend only on those grown at home. Trade makes it possible for her surplus manufactured goods to be traded abroad for the agricultural products that would (42) be lacking. A country’s wealth is, therefore, much (43) by its manufacturing capacity, (44) that other countries can be found ready to (45) its manufactures.

A.in

B.about

C.at

D.on

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