一. 祈使句的特殊结构

1、no 名词或动名词

No smoking. 不许吸烟

2、have done＋动名词

Have done beating him ! 不要再打了

3、be 形容词或名词

Be careful! 小心

4、be 过去分词

Be seated,Please! 请坐

5、be 现在分词

Don't be sitting down when headmaster is talking! 请不要在校长讲话时坐下！

6、do 祈使句

Do save us! 天哪！

7、与附加疑问句连用

Open the door,will you?开下门，好吗？

二. 祈使句与陈述句的转换

(1)普通祈使句=You must …

Come here .=You must come here.

(2)Please 祈使句=Will you (please) ～?

Please help me .=Will you (please) help me

三. 祈使句与条件句的转换

祈使句有时相当一个“if”引导的条件状语从句。

eg. Use your brain and you'll answer the question.= If you use your brain，you'll answer the question.

四. 直接引语和间接引语转换，其常用结构为“ask/request/tell/order sb(not)to do sth“。

eg.“Sit down，please!” the teacher said to me．=The teacher asked me to sit down.