if和whether都可以用在间接引语中,在ask,wonder,know,tell等动词后面,表示“是否”的意思。whether后可跟ornot,也只有whether可以放在不定式前面或者放在介词的后面。例如:SheaskedmeifI Both if and whether can be used in indirect speech, after the verbs such as ask, wonder, know, tell, and so on, to indicate the meaning of “no ”. Whether it can be followed by ornot, and only whether or not you can be in front of an infinitive or behind a preposition. For example: SheaskedmeifI