一、连接词that，whether，if引导的名词性从句
[观察例句]
1．It is possible that caffeine may cause birth defects(缺陷)in humans，too.
2．She asked me whether/if I had returned the books to the library.
3．Whether it is true remains a question.
4．The question is whether it is worth doing.
5．I think (that) you should turn to the teacher for help.
6．My reason is that the cost will be too high.
7．The news that I have passed the exam is true.
8．The question whether he will join us is very important.
