初中英语必考句型详解-70：till/until及not...until...句式（续1）

4. not...until...句式的强调句，不用倒装语序。

He invented many new ways to treat the wounded, but it was not until after the war that he made his most important discovery. 他发明过许多新方法来医治伤员，但是直到战后才有了最重要的发现。

5. not...until...句式与其他句式的比较

① not...until...句式总有“动作发生较迟”之义。

Among the great mathematicians there are about as many who showed mathematical talents in childhood as there are those who showed none at all until they are older. 在伟大的数学家中，童年就显露数学才华的人和直到相当年龄才显露才华的人差不多一样多。

② not...before...仅用表示动作先后关系，若主句谓语用一般将来时not...until...与not...before...意义相同。

It won't be long before you regret what you have done. 不久后你就会后悔你做的事。

Don't start smoking before a dinner is finished. 饭后才能抽烟。

③ Not...unless...常用来表条件，其主句的谓语常用一般将来时，而且unless只能接从句。

The doctor will not carry on the operation unless it is necessary. 到必要时医生才动手术。

【牛刀小试】

1. We won't start the meeting _____ our teacher arrives.

（2010天津）

A. though

B. until

C. while

D. or

2. Usually, we don't know how important something is _____ we lose it.

（2010鸡西）

A. or

B. until

C. as soon as

3. We'll visit Expo 2010 Shanghai this Sunday _____ it rains or it's very hot.

（2010苏州）

A. since

B. if

C. unless

D. until