④从句后有"or not"。

　　⑤后接动词不定式时。

　　Whether there is life on the moon is an interesting question.

　　月球上有没有生命是个有趣的问题。

　　The question is whether she should have a low opinion of the test.

　　现在的问题是她是否应该对这次测试有较低的评价。

　　Everything depends on whether we have enough money.

　　一切要看我们是否有足够的钱。

　　[即时演练1]　用that/whether/if填空

　　①That the college will take in more new students this year is true.

　　②Whether he can finish this task on time is of great importance.

　　③The students asked the question if/whether the book was worth reading.

　　④Let me know whether or not you can come.

　　⑤I don't know if/whether he still lives there after so many years.

　　⑥We are interested in whether you will attend the meeting.

　　⑦Give me your promise that you will come to our party this evening.

　　⑧He has made it clear that he will not give in.

　　3．疑问词who, whom, whose, what, which, where, why, when, how

　　疑问词引导的名词性从句由特殊疑问句转化而来。它们的特点是：

　　(1)疑问词保留自己的疑问含义；

　　(2)疑问词在从句中担当句子成分，如主语、宾语、定语或状语；

　　(3)这种疑问词引导的从句一律用陈述语序，不能用疑问语序。

　　Do you know whom they are looking for?

　　你知道他们在找谁吗？

　　I don't know whodid it.

　　我不知道这是谁干的。

　　[即时演练2]　选词填空