2015年卫生类职称英语考试语法知识：

1、由as soon as, immediately, directly, instantly, the moment, the second, the instant, the minute, the while 等引导的时间状语从句。这些连词都表示“一……就"。例如：

I will go there directly I have finished my breakfast.

The moment I heard the news, I hastened to the spot.

【注意】hardly(scarcely, rarely)…when / before, no sooner…than相当于as soon as之意。主句用过去完成时，从句用一般过去时。当hardly, scarcely, rarely和no sooner位于句首时，主句应用倒装语序。例如：

He had no sooner arrived home than he was asked to start on another journey.

No sooner had the sun shown itself above the horizon than he got out of bed to commence work.

由by the time引导的时间状语从句。

在一般情况下，如果从句的谓语动词用一般过去时，主句的谓语动词用过去完成时;如果主句的谓语动词用一般现在时，主句的谓语动词用将来完成时或将来进行时。例如：

By the time you came back, I had finished this book.

By the time you come here tomorrow, I will have finished this work.

By the time you come back tomorrow, I will be having lessons in class.

By the time you arrived home, I will be studying in this university.

2、由each time\every time\next time/last time/every time/the first time,和whenever/no matter when引导的时间状语从句。例如：

Each time he came to Harbin, he would call on me.

Whenever that man says"To tell the truth", I suspect that he's about to tell a lie.

No matter when she says"to tell the truth", I suspect that he’s about to tell a lie.

3、由as long as和so long as引导的时间状语从句。这两个连词表示“有多久……就多久"或者“只要"。如 　　You can go where you like as long as you get back before dark.

I will fight against these conditions as long as there is a breath in my body!

You can stay as long as 10 days.