祈使句(Imperative Sentence)用于表达命令、请求、劝告、警告、禁止等的句子叫做祈使句，祈使句最常用于表达命令，因此在学校文法中也常称为命令句。
1、肯定句：动词原型
Come here, please.
Go downstairs, please.
Stand up.
Sit down.
Be quiet.
Be careful.
2、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.