只用,浅谈if与whether区别写作策略

：if和whether的用法有多的同学会混到一块。有一同学是不管三七二十一，见到 ‘’就用 whether , 另外一同学则相反，一律用if。实际上，这兄弟两个的区分还是显著的。
词：if；whether；区别

一、只用if的情况。

在条件状语以句中，只用if.
If you see him, give him this note. 要是见到他，就把这便条给他。
If necessary, I can come at once. 必要，我马上就来。
在 as if=as though 引导的方式状语以句中，只用if.
It sounds as if you had a good time.
The animal was walking as if it had hurt its leg.
在even if=even though引导的让步状语以句中,只用if。
Even if you did see someone, you can’t be sure it was him.几世你有人，你也确定是他。
在感叹句中，用if only表示“要。。。。。。就好了”，此时多用虚拟语气。
If only I had the chance !==I wish I had the chance !
我要是有机会就好了！
在习惯口语用法中，只用if.
if so;if not.
Do you like coffee ? If so, he a cup of coffee. If not, I’ll make you a cup of tea.
if and when “倘若。。。”
If and when we ever meet again, I hope he remembers what I did for him.
倘若还能见面的话，我希望他能记住我为他所。
if anything 用语表达，多表示反面意见。
I’d say he was more like his father, if anything.
依我看，非要说他像谁的话，他比较像他的父亲。
She is not thin—if anything she’s on the plump side.
她并不瘦，相反，她还有点胖呢。
if做名词表示“不确定的情况”,常构成ifs and buts惯用结构。
If he wins---and it’s a big if---he will be the first Englishman to win for fifty years. 假设他赢了---不过个很大的疑问---他将五十年来个获胜的英国人。
There are still a lot of ifs and buts before everything’s settled.在得以解决还有不定因素。

二、只用whether 的情况

在名词性以句中，才会出现之间的辨析。在要求以yes或no作答的转述疑问句中，互换。在选择时，亦可互换。She asked if / whether I wanted a drink.He didn’t know if / whether we should write or phone.（会到，上述两种情况都出现在宾语以句中）在句中有or not时，只用whether。I wonder whether it is big enough or not.我想知道它大。

3. 引导主语、表语、同位语以句时，只用whether.

Whether it is true remains a question. 主语以句
到底是真是假还是个理由。
The question is whether he can come on time.表语以句
理由是他能否按时来到。
The question whether it is right or wrong depends on situation.
同位语是非理由要看情况而定。
4．做介词宾语时，只用whether。I hen’t decided the question of whether I’ll go back home.我还没决定回家理由。
5. 放在不定式，与不定式构成词组时，只用whether。He hasn’t decided whether to go there with her.他还没决定和她一起去那里。
在由discuss 、consider、 decide引导的宾语以句中，习惯用whether。We discussed whether we should close the shop.讨论该把商店关上。
whether 也引导让步状语以句，意为 “不管，无论’。Whether you like it or not, you’ll he to do it.无论你喜不喜欢，你都做这件事。Whether sick or well, she is always cheerful.不管生病与否，她总是高高兴兴的。