if釋義

conj. 即使; 如果，倘若; 〈口〉是否; 假設(shè);

n. 條件，設(shè)想;

if的用法

if從句一般有三種用法

1、主將從現(xiàn) （主句為一般將來(lái)時(shí),從句為一般現(xiàn)在時(shí)）；

eg:If it rains(從句) ,I will stay at home（主句）.

=I will stay at home if it rains.

2、主句含有情態(tài)動(dòng)詞 （must、may、can etc.）從句為一般現(xiàn)在時(shí)；

eg:If you drive too fast ,you may have an accident.

=You may have an accident if you drive too fast

3、主句為祈使句,從句要用一般現(xiàn)在時(shí)態(tài)；

eg:Don't play computer games if you don't finish your homework.

備注：

1、If 于句首時(shí)中間用逗號(hào)隔開(kāi),主句后不用逗號(hào).

2、if 可用unless(除非...) 替換.unless= if...not...

3、注意虛擬語(yǔ)氣 主句和從句都為一般過(guò)去式

eg:If I was a bird ,I could fly.（事實(shí)我不可能是鳥(niǎo)）

if相關(guān)詞組

if you want/like 如果你愿意的話(huà)

You can come and stay with us if you want.

if so如果是的話(huà)

Are you planning to return to work, and if so, who is going to look after the baby?

if not如果不是的話(huà)

Has anyone dealt with the technical problems? And if not, why not?

if necessary/if possible 如果必要/可能的話(huà)

We are ready to fight for our rights if necessary.

I should like to be back here by 10:30 if possible.

even if即使

I’d rather never sell this painting, even if they offered me a million dollars.

what if 要是……，那怎么辦？ 如果……那會(huì)怎樣？

What if the boss walked in here now and saw us?

as if好像是……

She always talks to me as if she was my sister.

if的用法例句

1、She gets very upset if I exclude her from anything

要是有什么事情我不讓她參加，她會(huì)非常難過(guò)。

2、He asked if I had left with you, and I said no

他問(wèn)我是否和你一塊兒離開(kāi)的，我說(shuō)不是。

3、Sometimes, that standard is quite difficult, if not impossible, to achieve

有時(shí)即便有可能達(dá)到那個(gè)標(biāo)準(zhǔn)，那也是非常困難。

4、If I could just make another small point about the weightlifters in the Olympics

請(qǐng)?jiān)试S我就有關(guān)奧運(yùn)會(huì)舉重運(yùn)動(dòng)員的問(wèn)題再補(bǔ)充一點(diǎn)。

5、I wonder if you'd be kind enough to give us some information, please?

請(qǐng)問(wèn)您能不能給我們提供一些信息？