一、祈使句：
1. 定义：用来表达请求，命令，劝告，警告，禁止等的句子；以动词原形开头，否定形式在句首加don’t；隐含主语为you;
e.g. Go and wash your hands.
Watch your steps.
Be kind to your sister.
2. 结构：
(1)Do型：
肯定结构；动词原型+其它成分
否定结构：Don’t+肯定结构
e.g. Eat in the classroom.
Don’t eat in the classroom.
(2)Be型：
肯定结构：Be +表语+其它成分
否定结构：Don’t+肯定结构
e.g. Be a good student!
Don’t be late for school!
(3)Let型：
肯定结构：Let+宾语+动词原形+其它成分
否定结构：Don’t+肯定结构
Let+宾语+not+动词原形+其它成分
e.g. Let him go.
Don’t let him go.
Let him not go.
3.祈使句的回答：祈使句通常用将来时来回答，如Ok, I will或者Sorry, I won’t。
e.g. Don’t speak loudly.
Sorry, I won’t.
Open your book, please.
Ok, I will.
4.句型：祈使句，and/or +句子（将来时）
(1)and表示递进，“这样做的话，就会怎么样”，结构为“祈使句，and+句子（用将来时）”；
e.g. Work hard, and you will get good grades.
Stay here, and you will know the truth.
(2)or表示否则，“这样做的话，否则会或不会怎么样”，结构为“祈使句，or+句子（用将来时）。
e.g. Work hard, or you won’t get good grades.
Take the umbrella, or you will get wet.
5.祈使句的反义疑问句：
(1)Let’s(包括说话者) 和let us（不包括说话者）句型中的反义疑问句；含有let’s的反义疑问句，需用shall we;含有let us的反义疑问句需用will you;
e.g. Let’s go to school together, shall we?
Let us do our homework, will you?
(2)以动词原形开头的反义疑问句的写法：若前半句为肯定，通常用will you;若为否定，则用won’t you。
e.g. Don’t speak loudly, will you?
Stay at home tonight, won’t you?
二、感叹句：
1.定义：用来表达喜、怒、哀、乐等强烈感情的句子叫感叹句。感叹句一般用what或how引导，句末用感叹号。what修饰名词，how修饰形容词或副词。
(1) what引导的感叹句:
①What + a/ an + adj. + 可数名词单数(+主谓语)!
e.g. What a brave boy (Tom is)!
What an excellent idea (it is)!
②What + adj. + 可数名词复数(+主谓语)!
e.g. What beautiful pictures (they are)!
③What + adj. + 不可数名词(+主谓语)!
e.g. What delicious food (it is)!
(2) how引导的感叹句：
How + adj. / adv. + 主语 + 谓语!
e.g. How happy the children were!
How carefully he is reading!
(3)注意：一般情况下，以what和how开头的感叹句可以相互转换，转换后意义不变。
e.g. What a tall building it is!
= How tall the building is!