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【单选题】
以下关于物理层的描述中,错误的是A.
物理层的主要任务是保证比特流通过传输介质的正确传输
B.
连接物理层的传输介质可以有不同类型，如光纤与无线通信线路等
C.
物理层协议可以分为基于点 - 点通信线路与基于广播线路两类
D.
物理层屏蔽了 Ethernet 与 IP 的差异性
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【单选题】He ___________ the volunteer group last year and ___________ many activities since then.
A.
took part in…joined
B.
joined…took part in
C.
joined…has taken part in
【简答题】others learn policeman difference happy stop those what from difficult Want an “OK” from your parents when you start to miss your favorite on-line ? It’s 小题1: but possible now. Last w...
【单选题】What does the sentence 'On the Internet, nobody knows you're a dog.' imply in the last paragraph?
A.
Even dogs are interested in the computer.
B.
E-mail has become very popular.
C.
Dogs are liberated from their usual duties.
D.
E-mail deprives dogs of their owners' love.
【简答题】What can we learn from the last sentence of the article?
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