感叹句

1）What +名词+主语+谓语

What a beautiful girl she is!
What tall buildings they are!

2）How +形容词+主语+谓语

How beautiful the girl is!
How tall the buildings are!

• 在口语中，感叹句的主语和谓语常常省略：

What a nice present!（省略it is）
How disappointed!（省略she is或其它可作本句主、谓的词语）

祈使句

     祈使句表示请求、命令、建议、邀请等，谓语动词一律用原型，句子中通常不用主语，句末用惊叹好或者句号，用降调。

★肯定句：动词原型

Come here, please.
Go downstairs, please.
Stand up.
Sit down.
Be quiet.
Be careful.

祈使句中如果有唤语，一定要用逗号隔开，放在句首或者句尾：
Come in, Amy.
Sit down here, Tom.
Mary, give me a book please.

★否定：Don't+动词原型

Don't come here.
Don't sit down.
Don't stand up.
Don't give me it.

let sb. do 让某人做

Let me pass.
Let us have a rest.
Let's have a rest.

反意疑问：
Let's have a walk along the river, shall we?
Let us go out for a drink, will you?