祈使句主要用来表达请求、命令、建议、叮嘱或祝愿等.祈使句通常省略主语（you）,但为了加强语气有时可以加上主语you或增加称呼.例：You be quick!你快点吧!Be quiet,girls!姑娘们,安静点儿!Have a good trip!（祝你）旅行愉快!1.句式a）行为动词开头的祈使句.例：Sit down.坐下吧!Come in.进来!Speaking loudly.大点声说!b）Be开头的祈使句,后常加形容词（系词开头）Be careful!当心!Be quick!快点!Be quiet!安静点!Keep silent!安静!c）Let…开头的祈使句Let me carry the box for you.让我替你拿这只箱子吧!Let the boy go home.让这个男孩回家.Let the teacher in first.让老师先进去.Let’s＋动词原形表建议,让我们….例：Let’s go fishing this Sunday.让我们这个礼拜日去钓鱼.Let’s have a rest.让我们休息一会.Let’s stay here.让我们留下来吧!Let’s = Let us.Let us 不同语境有不同的含义.Let’s “请让我们（咱们…）,包括谈话的对方.”例：Let’s go out and play football.咱们出去踢足球吧!Let’s have a rest!咱们休息一会吧!Let us 意为“请让我们……”表示希望得到对方允许,不包括对方.Let us buy you a drink.给你买杯饮料吧!Let us go.（Don’t stop us going.）请让我们走吧!2.祈使句的否定式,在句首加don’t,常用缩略式.例：Don’t be late for school.上学别迟到.Don’t be in such a hurry.别那么忙.Don’t run so fast.别跑那么快.Let’s 的否定式可以有两种：Let’s not ＋动词原形或Don’t let’s ＋动词原形.例：Let’s not think about it.我们别想这事了.Don’t let’s think about it.Let’s not have a rest.我们别休息了.Don’t let’s have a rest.3.祈使句的反意问句以行为动词或系词be或keep开头的祈使句,如果是肯定形式,后加will you 或won’t you 构成.例：Listen to me carefully,will you （won’t you）?Pass me the book,will you （won’t you）?如果祈使句是否定形式,常用will you.例：Don’t speak so fast,will you?别说那么快,好吗?Don’t lie on the grass,will you?别躺在草地上,好吗?Let’s构成的祈使句,包括谈话双方,用shall we 构成.Let’s go for a walk,shall we?让我们出去散步,好吗?Let’s walk there,shall we?让我们走着去那,好吗?Let us 构成的祈使句,不包括对方,请求对方允许,用will you 构成.例：Let us go there now,will you?让我们去那儿吧,好吗?Let us copy the text,will you?让我们抄课文吧,好吗?注：（1）祈使句中常加do或always来加强肯定的语气,用never来加强否定的语气.例：Do be quiet a moment.务请安静一会儿.Always remember all your father has said,and be a good boy.要永远记住你爸爸的话,做一个好孩子.Never trouble trouble till trouble troubles you.麻烦不来找你,千万别去找麻烦.Never speak like that again.千万别再那样说话.（2）祈使句中常加上please,表示礼貌,更客气.please可以放句首,也可以放句尾.放句末时要用逗号分开.例：Please open the door.＝Open the door,please.请打开门.Please don’t forget the meeting.（Don’t forget the meeting,please.）请别忘记开会.
