试题与答案

通信电缆线路的串、杂音主要是由于哪些原因造成的。()A、电缆芯线错接、破坏了芯线电容

题型:多项选择题

题目:

通信电缆线路的串、杂音主要是由于哪些原因造成的。()

A、电缆芯线错接、破坏了芯线电容的平衡

B、线对接头松动,引起电阻不平衡

C、外界干扰源磁场窜人等影响而造成

D、断线

答案:

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题型:阅读理解

The world’s biggest Internet search engine, Google, has proven once again to be king of the Web. Users can download “Google Wi-Fi” software and then enjoy free Wi-Fi service available in some US cities since last Tuesday.

Wi-Fi is short for “Wireless Fidelity”(无线上网). It allows laptop computers and personal digital assistants to connect to the Internet at high speed by radio sigal.

A person with a Wi-Fi enabled computer can connect to the Internet when near one of the network’s access points. The place covered by one or several access points is called a hotspot. Google had already set up two “hotspots” in the US city of San Francisco which provide a free Wi-Fe service.

The Wi- Fi technology even allows users to enjoy a free Internet phone service. Some scientists argue that Wi-Fi may replace mobile phone networks.

Wi-Fi is stioo limited to a few cities, where there are “ hotspots”. But its capability(容量) of sending information has already done better than that of the mobile phone network, even that of 3G (Third Generation telecommunication technology). Some scientists have started to call Wi-Fi 4G.

In addition to a high speed Internet connection, Fi-Fi has other advantages compared to mobile phones. We-Fi is global. The same Wi-Fi system works in different countries around the world. Different from using cell phones, you don’t need to change computers to use Internet phones when you go to other places and most importantly, many Internet phones cost you nothing at all.

小题1: Wi-Fi is not available in cities without_____.

A.a computer

B.a radio

C.a hotspot

D.a cell phone小题2: Which of the following is NOT the advantage of Wi-Fi?

A. The high speed Internet connection.   B. Many free Internet phones.

B. Using the same computers for Internet phones when you go to other places. C. Used in all the US cities.

小题3: Some scientists started to call Wi-Fi 4G, because_____.

A.it is the product of the Google”s 4th generation.

B.it is more capable of sending information than the mobile phone network.

C.it has been used by more than four generations.

D.Wi-Fi will surely take the place of the mobile phone network.小题4:. Which of the following is the best title?

A.Third Generation Telecommunication Technology

B. Free Call Service

C.Google Launches Free Wi-Fi Service

D.Free Wi-Fi Service across the U.S.A.

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