if僅由兩個字母組成，是一個看上去很簡單的單詞，但是實(shí)際它的意思和用法都是很多的，那么接下來就來跟大家說一說if究竟包含有哪些意思。

簡要回答

if是一個英語單詞，既可以作名詞又可以作連詞，作名詞意為不確定的情況，作連詞意為如果、假若、倘若、當(dāng)、無論何時、每次，與will或would連用，表示客氣地請求。

詳細(xì)內(nèi)容

if
英 [?f] 美 [?f]
conj.如果;假若;倘若;當(dāng);無論何時;每次;與will或would連用，表示客氣地請求
n.不確定的情況
復(fù)數(shù)： ifs

語法說明
【if】【whether】
Both if and whether are used in reporting questions which expect ‘yes’ or ‘no’ as the answer if和whether均用于要求以yes或no作答的轉(zhuǎn)述疑問句中：
She asked if/whether I wanted a drink.
她問我要不要喝點(diǎn)什么。
although whether sounds more natural with particular verbs such as discuss , consider and decide . When a choice is offered between alternatives if or whether can be used. 不過whether與discuss、consider和decide等動詞連用聽起來更自然。提供選擇時用if或whether均可：
We didn’t know if/whether we should write or phone.
我們不知道是寫信好還是打電話好。
In this last type of sentence, whether is usually considered more formal and more suitable for written English. 在最后這一句型中，一般認(rèn)為whether較正式，更適用于書面英語。

雙語例句
She gets very upset if I exclude her from anything
要是有什么事情我不讓她參加，她會非常難過。
He asked if I had left with you, and I said no
他問我是否和你一塊兒離開的，我說不是。
Sometimes, that standard is quite difficult, if not impossible, to achieve
有時即便有可能達(dá)到那個標(biāo)準(zhǔn)，那也是非常困難。
If I could just make another small point about the weightlifters in the Olympics
請?jiān)试S我就有關(guān)奧運(yùn)會舉重運(yùn)動員的問題再補(bǔ)充一點(diǎn)。
I wonder if you'd be kind enough to give us some information, please?
請問您能不能給我們提供一些信息？
If there was any disappointment it was probably temporary
即便有點(diǎn)兒失望，也肯定是暫時的。