音标：[if]
conj. 如果, 是否, 无论何时, 假设, 即使
n. 条件
【计】 DOS批处理命令:根据所测试的条件决定是否执行另一条命令
相关词组:
If weather permits...
if only
if so
as if
if at all
if it had not been for
if I were you
在线英汉词典

if的短语、例句：

f conj 1 on condition that; supposing 假如; 如果; 倘若; 要是. (a) (used with the present and present perfect tenses for highly predictable situations 与现在时态和现在完成时态连用表示预料到的情况)
I´ll only stay if you offer me more money. 假若你肯多给钱, 我就留下.
If you have finished eating you may leave the table. 你要是吃完了, 就可以离席了.
If (it is) necessary I will come at 6. 如有必要, 我6点钟来.
You can stay to dinner if you like. 你愿意的话, 可以留下一起吃饭.
If anyone calls tell them I´m not at home. 有人来电话, 就说我不在家.
(fml 文) If the patient should vomit, turn him over with his head to the side. 倘若病人要呕吐, 就帮他翻过身来, 头侧向一边. (b) (used with a past tense for imaginary situations 与过去时态连用表示假想的情况)
If you learned to type you would easily find a job. 假使你学过打字, 就容易找工作了.
If he were here I could explain to him myself. 要是他在这里, 我就可以亲自向他解释了.
If I was a man they would have given me the job. 我要是男的, 这份工作就准给我了.
Would she tell us the truth if we asked her? 我们问她, 她会告诉我们实情麽?
If you liked (ie With your approval) I could ask my brother to look at your car. 你要同意的话, 我可以叫我弟弟来给你检查一下汽车.
They would have been here by now if they´d caught the early train.他们要是赶上了早班火车, 现在都该到这儿了.
I wouldn´t have believed it possible, if I hadn´t seen it happen. 要不是亲眼目睹, 我决不会相信能有这种事. =>Usage at unless 用法见unless. 2 when(ever) 无论何时; 当: If metal gets hot it expands. 金属遇热则膨胀.
She glares at me if I go near her desk. 我一走近她的办公桌, 她就瞪我. 3 (used with will and would as the first part of a sentence when making a polite request 与will和would连用, 作复合句的前部, 用以提出请求显得客气)
If you will sit down for a few moments (ie Please sit down and) I´ll tell the manager you´re here. 请稍坐, 我这就通知经理说您来了.
If you would care to leave your name, we´ll get in touch as soon as possible. 请留下您的名字, 我们尽快和您联系. 4 (used after ask, know, find out, wonder, etc to introduce alternatives 用於ask、 know、 find out、 wonder等之後, 以引导含不同可能性的情况) whether 是否
Do you know if he´s married? 他结婚没结婚, 你知道吗?
I wonder if I should wear a hat. 我不知道该不该戴帽子.
He couldn´t tell if she was laughing or crying. 他弄不清她是笑还是哭.
Listen to the tune see if you can remember the words. 请听这曲子--看你能不能想得起歌词来. 5 (used after vs or adjs expressing feelings 用於表示情感的动词或形容词之後)
I am sorry if I´m disturbing you. 很抱歉, 打搅您了.
I´d be grateful if you would keep it a secret. 如予保密, 无任感激.
Do you mind if I switch the radio off? 我可以关掉收音机吗? 6 (also even if) (used when admitting that sth may be true or may happen 用於承认某事可能属实或可能发生) although 即使; 纵然; 虽然
If he said that, he didn´t expect you to take it personally. 即使他是那样说的, 他也并不是针对你个人而言的.
Even if you saw him pick up the money, you can´t be sure he stole it. 就算你看见是他拾起的钱, 你也不能肯定钱就是他偷的. 7 (used before an adj to introduce a contrast 用於形容词之前, 以引导一对比情况) although also 虽然; 尽管
It was thoughtless if well-meaning. 用意虽好, 考虑欠周.
He´s a real gentleman, if a little pompous at times. 他可是个正人君子, 虽然有时略显得傲慢了些. 8 (used to express surprise, astonishment, dismay, etc 用以表示意外、 惊奇、 沮丧等)
If it isn´t my old friend Bob Thomson what a coincidence! 这不是我的老朋友鲍勃?汤姆森吗--真巧哇!
If that´s not the best idea I´ve heard in a long time! 很久没听到过这麽好的意见了啊!
If he hasn´t gone and got into trouble with the police! 他竟然跟警方惹上了麻烦! 9 (used before you think, ask, remember, etc to invite sb to listen to one´s opinion 用於you think、 ask、 remember等之前, 请对方听自己的意见)
If you ask me, she´s too scared to do it. 依我说, 她是吓得不敢去做.
If you think about it, those children must be grown-up by now. 想想吧, 那些孩子现在一定都长大成人了.
If you remember, Mary was always fond of animals. 记得吗, 玛丽一向喜欢动物. 10 (idm 习语) ,if and `when (used to express uncertainty about a possible event in the future 用以表示怀疑将来的事能否发生)
If and when we ever meet again I hope he remembers to thank me. 倘若我们再有见面之时, 希望他不会忘记谢我. if ,I were `you; if ,I was/were in `your shoes/place (used to introduce a piece of advice to sb 用以引导出劝告某人的话)
If I were you I´d start looking for another job. 我要是你, 就去另找工作了.
If I were in your shoes, he´d soon know what I thought of him. 若是我处在你的地位, 他很快就会知道我对他的看法了. if `anything (used to express a tentative opinion or after a negative statement to say that the opposite is true 用以表达无把握的看法, 或用於否定的话语之後, 表示所说的是反话) if anything definite can be said, this is it 若能稍有把握地说出来, 其实是这样
I´d say he was more like his father, if anything. 若非要说出像谁不可来, 我倒认为他略微像他父亲.
He´s not thin if anything he´s rather on the plump side. 他可不瘦--按说还算有点胖呢. if `not (a) (used after if and a v in the present or present perfect tense 用於if +动词（现在时态或现在完成时态）之後) otherwise 要不; 不然
I´ll go if you´re going if not I´d rather stay at home. 你去我就去, 否则我宁可待在家里.
If you´ve finished we can have a coffee if not, you´d better keep working. 你要是完事了, 咱们可以喝杯咖啡--不然的话, 你最好接著干下去. (b) (used after a yes/no question to give a promise, warning, etc 用於yes/no疑问句之後, 表示许诺、 告诫等)
Are you ready? If not, I´m going without you. 准备好了吗? 要不, 我就自己去了. if `only (a) (used to express a wish with reference to present or future time 用以表示对现时或未来的愿望)
If only I were rich. 但愿我很富.
If only I could swim. 要是我会游泳该多好.
If only I knew her name. 我要是知道她的名字就好了.
If only it would stop raining. 真希望雨能停.
If only they would tell me what they´ve decided. 但愿他们能把决定告诉我. (b) (used to express a wish that past events had been different 用以表示与过去事实相反的愿望)
If only he´d remembered to buy some fruit. 他当时要是记得买些水果来该多好.
If only I had gone by taxi. 假若我是乘计程车去的就好了. only if (when used at the beginning of a sentence, making the v in the following clause precede its subject 用於句首, 後接从句主谓倒装) only on condition that 只要; 只有
Only if a teacher has given permission is a student allowed to enter this room. 只有得到教师的允许, 学生才可以进这间屋.
Only if the red light comes on is there any danger to employees. 只要红灯一亮, 就表示有危及职工的险情. if, n (infml 口) 1 uncertainty 不确定的事; 无把握的事
If he wins and it´s a big if he´ll be the first Englishman to win for twenty years. 假使他赢了--是否能赢还是一大疑问--他将是二十年来第一个获胜的英国人. 2 (idm 习语) ,ifs and `buts reservations; arguments against sth 保留意见; 对某事物的辩解
Now I´m not having any ifs and buts it´s cold showers for everyone before breakfast tomorrow. 好了, 不要跟我讨价还价--明天早饭前大家都要用冷水淋浴. if, NOTE ON USAGE 用法
Both if and whether are used in reporting questions which invite yes/no answers or offer a choice between alternatives *if和whether均用於间接疑问句, 要求回答yes/no或提供选择
(`Do you want a drink?´) He asked whether/if we wanted a drink. （｀你们想喝点东西吗?＇）他问我们是否要喝点东西.
He didn´t know whether/if we should write or phone. 他不知道我们是写信好呢还是打电话好. Whether (NOT if) can be followed by an infinitive *whether後面可接不定式（if不可这样用）
I´m not sure whether to resign or stay on. 我拿不准主意是辞职还是留任. After a preposition whether must be used 在介词之後只能用whether
It depends on whether the letter arrives in time. 这取决於信是否来得及时. Whether is also used when the clause it begins is the subject of a sentence *whether还可用以引导主语从句
Whether they win or lose is all the same to me. 他们是赢是输於我都一样. Whether (NOT if) can be immediately followed by `or not´ *whether後面可直接用or not（if不可这样用）
I´ll be happy whether or not I get the job (compare 试比较
I´ll be happy whether/if I get the job or not 我能不能得到那份工作都一样高兴).