疑問詞why引導的省略句中的不定式在當代英語中一般須省去to。如：

1. 肯定形式

Why talk so much about it? 這樣大談它干嘛?

You’re fully insured, so why worry? 你已經(jīng)全部保險了，那何必還擔心呢?

Why ask me? How should I know? 為什么問我? 我怎么知道?

一I think I ought to tidy this place up. 我想我應該把這地方清掃一下。

一Why bother? 何必麻煩呢?

2. 否定形式

Why not try again? 干嘛不再試呢?

Why not go now? 現(xiàn)在就去好不好?

Why notjust wait and see what happens? 何不靜觀其結果呢?

Why not try to expand your story into a novel? 你怎么不把你的故事擴展成小說呢?

Why not wait till the winter sales to buy a new coat? 為什么不等到冬季大賤賣時再買一件新外衣呢?

3. why not單獨使用

I’m not going to work today. 一Why not? 我今天不去上班了。——為什么不呢?

Let’s eat out tonight. 一Yes, why not? 我們今晚出去吃飯吧。——對，為什么不呢?

Are you really going to sue them?一Yes, why not? 你真的打算控告他們嗎?——是的，為什么不呢?

4. 與非省略句的替換

對于一般現(xiàn)在時而言，它可與非省略句轉(zhuǎn)換：

你為什么不找點事干，比如給我擦洗汽車?

正：Why not find something to do, like cleaning the car for me?

正：Why don’t you find something to do, like cleaning the car for me?

對于一般過去時而言，它不能與非省略句轉(zhuǎn)換——只能用非省略形式，不能用省略句：

為什么你沒告訴我約翰已經(jīng)離開了你?

正：Why didn’t you tell me John had left you?

誤：Why not tell me John had left you?