在英语(Q吧)学习中,好多同学对如何使用whether和if 感到模糊,常常误用。下面我们分别来看一下whether和 if 的用法。
一、只用 whether 的情况:
1 在表语从句和同位语从句中只能用whether表“是否”。如:
He answered my question whether he would come .
The news whether our team has won the game is not known.
The question is whether the book is worth baying.
2 当主语从句位于主语位置上时,只能用whether表“是否”。如:
Whether it will rain is not clear .
Whether they will come in time is a question .
3 在介词后面引导宾语从句表“是否”,只能用whether。如:
It all depends on whether they will support us .
The discussion focused on whether they would buy a new car .
4 后面直接跟动词不定式时,只能用whether表“是否”。 如:
I don’t know whether to stay or not. .
5 后面紧跟or not 时。如:
We didn’t know whether or not she was ready .
6 引导让步状语从句时,只能用whether 。如:
Whether you like it or not ,you must do it well .
7 用if会引起歧义时。如:
Please let me know if you like it .
这个句子可有两个意思:“请告诉我你是否喜欢。”或“如果你喜欢,请告诉我。”用whether就可以避免歧义。
二、只用 if的情况
1引导条件状语从句时。如:
If it doesn’t rain tomorrow , we will go hiking .
If you like it , you can take it .
2 和 even连用时。如:
Even if the job was difficult , they did it well .
Even if it’s sunny , it a bit cold .
三、if , whether 均可使用的情况
1 引导宾语从句。如:
I wonder if / whether the news is true or not .
2 在 “ be + 形容词 ”之后。如:
He was not sure if / whether it is right or not .
3 主语从句中使用了形式主语it,主语从句后置时。如:
It hasn’t been decided if / whether we shall have a class meeting .
[责任编辑:moninfu]