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问题 单项选择题

小型局站ODF架中的高压防护接地装置应用何种规格的电力电缆与机房总接地汇接排连接（）。

A.不少于6mm2的铜接地线

B.不少于16mm2的单股铜芯接地线

C.不少于16mm2的多股铜芯接地线

D.不少于35mm2的多股铜芯接地线

答案

参考答案：D

单项选择题

要设计出带表格线的报表，完成表格线的显示需要向报表中添加______控件。

A．复选框

B．标签

C．文本框

D．直线或矩形
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单项选择题

Many people are surprised when they find the Internet(因特网)was set up in the 1960s. At that time, computers were large and expensive. Computer networks(网络) didn’t work well. If one computer in the network broke down, then the whole network stopped. So a new network system (系统) had to be set up. It should be good enough to be used by many different computers. If a part of the network was not working, information could be sent through another part. In this way computer network system would keep on working all the time.
At first the Internet was only used by the government, but in the early 1970s,universities(大学) ,hospitals and banks were allowed(允许) to use it too. However, computers were still very expensive and the Internet was difficult to use. By the start of the 1990s, computers became cheaper and easier to use.
Today it is easy to get on-line(上网) and it is said that millions of people use the Internet every day. Sending e-mail is more and more popular among students.
The Internet has now become one of the most important parts of people’s life.

The Internet has a history of ______ years.

A. less than 30

B. about 40

C. about 20
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