whether和if都可以引导宾语从句,表示“是否”,在口语或间接引语中两者可以互换使用。如:1 2
| I wonder if / whether I can get some advice from you. Ask him whether / if he can come.
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但在有些情况下,whether和if的用法有一定区别。
whether引导的从句常可以与连词or或or not直接连用,而if一般不能。如:
1 2
| 正: Let me know whether you can come or not. 误: Let me know if you can come or not.
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当宾语从句提到句首时,只能用whether引导,而不能用if。如:
1 2
| 正: Whether it is true or not, I can’t tell. 误: If it is true or not, I can’t tell.
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whether可以引导带to的不定式,if则不能。如:
1 2
| 正: I don’t know whether to accept or refuse. 误: I don’t know if to accept or refuse.
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whether及其引导的成分可放于介词之后,作介词的宾语,但if不能。如:
1 2
| 正: I worry about whether I hurt her feelings. 误: I worry about if I hurt her feelings.
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whether可以引导从句,作主语、表语或同位语,而if不能。如:
1 2 3 4 5 6 7 8
| 正: It was uncertain whether he would come. 误: It was uncertain if he would come.
正: His first question was whether Tom had arrived yet. 误: His first question was if Tom had arrived yet.
正: We must consider the question whether we will take these measures. 误: We must consider the question if we will take these measures.
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