祈使句的反意疑问句
1．祈使句的反意疑问部分为肯定形式,要用shall,will.如：
    Pass me the book,will you?
2．Let’s表示第一人称的祈使句,反意疑问句为“Shall we?”.如：
    Let’s go for a walk,shall we?
    Let’s forget it,shall we?
3．Let me和Let us 表示第二人称的祈使句,反意疑问句为“will you?”.如：
    Let us go for a walk,will you?
4．其它行为动词引起的祈使句,无论其陈述部分是否定还是肯定的祈使句,多用“will you?”,表一种客气的语气.如：
    Listen to me,will you?
    Don’t tell anyone about it,will you?
但在肯定的祈使句后有时也用“won’t you?”表“提醒对方注意”或表“邀请”.如：
    Have a cup of coffee,won’t you?
    Come in and take a seat,won’t you／will you?
祈使句用于两个重要句型中
1．“祈使句+and+表结果的陈述句”用来叙述肯定的条件.
2．“祈使句+or(else)+表结果的陈述句”用来叙述否定的条件,or(else)表示“否则；要不然”.试比较：
      Hurry up and you’ll catch the train.(＝If you hurry up,you’ll catch the train．)
      Hurry up,or you’ll miss the train．(＝If you don’t hurry up,you’ll miss the train．)
祈使句由直接引语变成间接引语
当祈使句由直接引语变成间接引语时,其常用结构为“ask／request／tell／order sb(not)to do sth”.
如：“Speak loudly,please!” the teacher said to me．(＝The teacher asked me to speak loudly．)
     “Don’t smoke in the meeting room!” he said to Tom．(＝He told Tom not to smoke in the meeting room．)