英语时态固定不变的句型

在英语句子结构中，时态的变化是比较灵活的。但是在一些句子中， 时态的变化是是不变的。如下面的句子：

(1)主语+will+动词原形+if(when,unless)+主语+一般现在时；

eg. I will tell him about it when he comes.

当他来时，我会告诉他。

(2 ) was/ were doing…… when +一般过去时；

eg.He was walking in the street when he heard a cry for help.

他正在街上走，突然听到一个呼救声。

(3) was/ were about to do…… when +一般过去时；

eg.I was about to jump into the river when I was stopped.

我正要跳河游泳，突然我被拦住了。

(4 )This/That/It is the +序数词+ time + that +现在完成时；

eg. It is the first time that I have been here.

这是我第一次来到这里。

(5)This/That/It was + the +序数词+ time + that +过去完成时；

(6)It is/has been +时间段+ since +一般过去时；

eg. It has been years since I last saw you.

自从上一次来到见你，到现在有几年了。

(7) hardly…… when…….，no sooner…… than……，hardly/ no sooner后用过去完成时，when/than后用一般过去时。

eg.No sooner had he realize it than he was knocked down.

他还没有意识到这一点，就被撞到了。

（8）虚拟语气中的时态（内容较多，单列出。敬请关注）

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