546　not...until/till和not...before

　not...until 是一种常用句型，意为“不到……不，只到……才……，之前……不……”。until前的句子用否定式，until后可跟从句，用肯定式，也可跟短语，作时间状语。not...until 中的until表示“直到”，not...before 中的before表示“在……之前”，这两个句型常可换用。

He won't leave until/before 10 o'clock. 他要到10点钟才会离开。/他10点钟之前不会离开。

I can not give the box to you until/before I see Mary. 见到玛丽我才能把那只箱子给你。/见到玛丽前我不能把那只箱子给你。

They didn't stop talking until the clock struck twelve. 直到钟敲响12点他们才停止谈话。

I didn't know the truth until then. 我直到那时才了解事实真相。

It is not until the bell rang that I realized that it was past midnight. 直到铃响了我才意识到午夜已过。

Until you told me about it the day before yesterday, I had no idea of it. 直到你前天告诉我，我才知道。

提示

如果主句谓语动词是延续性的，表示“直到……才”时，该动词可用肯定式或否定式；如果主句谓语动词是非延续性的（go, start, leave等），表示“直到……才”时，该动词只能用否定式。

He won't stay here until she comes. 他在这里将不待到她来。

She won't live here until next month. 她在这里将不住到下个月。

I didn't wait until he returned. 我没有等到他回来。

He won't go until six o'clock. （正）要到6点钟他才去。

He will go until six o'clock. （误）