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易混點whether與if區(qū)別

二者都可以作“是否”講，能引導(dǎo)名詞性從句，都不能省略。

1.）在及物動詞后引導(dǎo)賓語從句時可以互換；

注意：在某些動詞后（如:discuss）只能接whether，不能跟if。如：

We discussed whether we should close the shop.

2.）引導(dǎo)主語從句、表語從句、同位語從句時都用whether，不用if。如：

The question whether he should come himself or send another man hasn’t been decided.

Whether he will win is all the same to me.

The question is whether you can go there yourself.

如果用形式主語，if和whether都可以

It is unknown whether\if she is ill.

3.）如果whether后緊跟or not，不用換做if；若whether與or not分開使用，則可以換作if。如：

I wonder whether or not he has arrived at the destination.

I don’t know whether\if I can come or not.

4.）若賓語從句為否定結(jié)構(gòu)，則多用if，而不用whether。如：

I don’t care if he doesn’t show up.（在乎，炫耀）

5.）在介詞后引導(dǎo)賓語從句或與帶to的動詞不定式結(jié)合而構(gòu)成不定式的復(fù)合結(jié)構(gòu)時，只能用whether，而不用if。如：

I haven’t settled the question of whether I will go back home.

She doesn’t know whether to get married now or wait.

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