祈使句的结构和用法
祈使句的结构有以动词原形开头的结构类型和以let开头的类型。用法有祈使句如要引用，多使用一个不定式、反意疑问句用will you/won't you。
一、以动词原形开头的结构类型：
在动词原形之前加do的结构类型：（但只限于省略第二人称主语的'句子）。例如：Take this seat.Do be careful.否定结构：Don't move.Don't be late.
二、以let开头的类型：
1、Let's包括说话者，例如：Let's have another try，shall we/shan't we?=Shall we have another try?
2、Let us不包括说话者例如，Let us have another try，will you/won't you?=Will you please let us have another try？否定结构：Let's not talk of that matter.Let us not talk of that matter.
三、祈使句如要引用，多使用一个不定式：
前面的谓语形式根据语气决定，如：Wake him up,she said.→She told me to wake him up.See a neurologist,the doctor said.→The doctor advised me to see a neurologist.
能跟这种结构的动词有：advise ask beg command forbid instruct invite order,persuade remind teach tell urge warn.
四、反意疑问句用will you/won't you：
以let's开头的祈使句的反意疑问句部分用shall we。以let us开头的祈使句的反意疑问句部分用will you/shall we。
如：Don't swim here,will you？不要在这游泳，好吗？Let's go to the zoo,shall we？让我们去动物园吧，好吗？
