When it comes to modern communication, network safety is always a major          . 

concern

advantage

opportunity

solution

考查名词辨析。句意：当涉及现代通信，网络安全一直是一个主要令人担忧的问题。A. concern关心，令人担忧的事实或情况；B. advantage 优势；C. opportunity 机会；D.solution解决方案。网络安全一直是现代通信的个主要令人担忧的问题。故选A项。

never I have read

never have I read

ever I have read

ever have I read

Dr.Rowan,           secretary resigned two weeks ago, has had to do all his own typing.

whose

of whom 

of which

which

考查定语从句。句意：罗文博士的秘书两周前辞职了，他只能自己打字。          secretary resigned two weeks ago是非限制性定语从句，修饰Dr.Rowan, 引导词在从句中作定语，表示“Dr.Rowan's”，表示“......的”，应用关系代词whose引导该从句。故选A项。

The salesman scolded the girl caught         and let her off.

to have stolen

to be stealing

to steal

stealing

考查非谓语动词。句意：这个销售员责备了被抓住正在偷东西的女孩，然后，让她走了。分析句子结构，caught是过去分词作定语，修饰前面的名词 the girl,"女孩"和"偷东西"之间是主动关系，用现在分词作宾语补足语，构成catch sb doing sth结构。意为抓住某人正在做某事。故选D项。

One of the man holds the view          the book said was right.

that

whether

what that 

that what

考查同位语从句及主语从句。句意：其中一个人认为这本书说的是对的。分析句子可知，the view后面接了一个同位语从句（     the book said was right.），从句句子成分齐全，应使用that 引导，连接词在从句中不做成分，无意义。在同位语从句中又有一个主语从句（     the book said），在主语从句中said 缺少宾语，应用what 引导，指代“......的（事情，东西）”。故选D项。