题目内容：

英语几道题求解 关于IT的用法
17.Which sentence is wrong?
A.I felt it impossible for him to take the exam.
B.I found it impossible that he might take the exam.
C.I thought that he might not take the exam.
D.In my opinion he might take the exam.
18.I don't think difficult for a Chinese student to master a foreign language within five years
A.that B.it C.too D.very
19.It's the second time you late this week.
A.arrive B.arrived C.have arrived D.had arrived
20.It will not be we meet again.
A.long before B.before long
C.soon after D.shortly after
这几道题我都选错了 不知道是什么原因帮忙解释下吧

优质解答

17.C
think否定用法 not应该在主句上.
I didn't think that he might take the exam.这样就对了.
AB里面的it都是指代take the exam这件事.
18.it
it在这里做形式主语,指代master a foreign language这件事
其实填写it is也是对的,但外国人不常这么用.
19.C
固定句式This is+次数+现在完成时
This was...+过去完成时
20.A
不久我们就会再次见面的.
这个句子应该这样看It won't be long / before we meet again.
不要将long before看成一个词组,因为long before是很久以前的意思,看成词组就会做错.
before long后面加的不是从句,所以不选.
还有两个应该不需要解释.