if

剑桥词典

if conjunction (IN THAT SITUATION)

used to say that a particular thing can or will happen only after something else happens or becomes true
假如，如果
I'll pay you double if you get the work finished by Friday . 如果你周五前完工，我付你双倍的报酬。
We'll have the party in the garden if the weather's good. If not (= if the weather is not good), it'll have to be inside. 如果天气好的话，我们将在花园里开派对。如果不好，就只好在室内了。
If anyone calls , just say I'll be back in the office at four o'clock. 要是有人给我打电话，请告诉他们我4点钟回办公室。
If she hadn't called, I wouldn't have known . 要不是她打来电话，我还不知道呢。
I wouldn't work for them (even ) if they paid me twice my current salary . 即使他们付给我的工资是现在的两倍，我也不会为他们干活。
We'll deal with that problem if and when it arises . 等到那个问题出现我们再处理。
If disturbed , the bird may abandon the nest , leaving the chicks to die . 如果受到惊扰，鸟可能会弃巢而去，留下雏鸟，任由它们死亡。

although
虽然，即使
They're great kids , even if they can be demanding . 虽然他们要求多多，但他们是很好的孩子。
literary It was a hot , if windy day . 那天虽然有风，却依然很热。
every time
当，每当
If water is heated to 100°C it turns to steam . 水被加热到100摄氏度时，就会变成蒸汽。
If I don't get enough sleep I get a headache . 我睡眠不足时就会头疼。

used to mean "if it is true that"
如果…是真的
I'm very sorry if I've offended you. 如果我冒犯了你的话，我很抱歉。

例句

• You'll feel cold if you don't wear a coat .
• You have to go to college for a lot of years if you want to be a doctor .
• Try to act confidently, even if you feel nervous .
• The TV won't work if the aerial's not connected .
• Biscuits will stay crisp if you keep them in an airtight container .

if conjunction (WHETHER)

used to introduce a clause , often in indirect speech , that shows two or more possibilities
（用于引出从句，常为间接引语）是否
Mrs Kramer called half an hour ago to ask if her cake was ready . 克雷默夫人半小时前来电话问她的蛋糕做好了没有。
I don't care if he likes it or not - I'm coming! 我不在乎他乐不乐意，我反正要来！
I was wondering if you'd like to come to the cinema with me this evening ? 不知你今晚想不想与我一起去看电影？
比较
whether

例句

• I must see if my flatmate has paid those bills yet .
• We asked if the computer could access the internet.
• You could always call Susie and see if she might babysit .
• I asked if she'd like to come out with us tonight .
• I couldn't find the station , so I asked someone if they could direct me.

if conjunction (REQUEST)


used when you want to make a polite request or remark
（用于礼貌地作出请求或评论）
If you'd like to take a seat , Mr Chang will be with you in a moment . 您请先坐一会儿吧，张先生一会儿就过来。
Would you mind if I open /opened (= can I open ) the window ? 我开窗您介意吗？
There are, if you don't mind me saying so, one or two problems with this plan . 恕我冒昧，我觉得这个计划有一两处问题。


习语

if and when
if I were you
if need be
if you will 返回 if