1、祈使句可省去主语，如：
Leave him in peace! 不要去打扰他!
Come at one o’clock sharp. 准一点钟来。
Listen to me, children! 听我讲，孩子们!
Look both ways before you cross the road. 过马路之前要向两边看看。
2、除祈使句外，还有其他省去主语的情况，如：
Don’t know. 我不知道。(省去主语I)
Beg your pardon. 请原谅。(省去主语I)
Had a good time, didn’t you?玩得很好，不是吗?(省去主语you)
Doesn’t look too well. 他脸色不大好。(省去主语he或she)
Looks like rain. 像是要下雨了。(省去主语it)
3、There be结构中的there有时也可省去，如：
Must be somebody waiting for you. 一定是有人在等你。
Appears to be a big crowd in the hall. 大厅里似乎有一大群人。
扩展资料：
英语中的主语一般不可省略，但在口语中某些惯用表达也可省略。如：
Beg your pardon. 请再说一遍。
Haven’t seen you for ages! 好久不见了!
Second the motion! 附议!
Doesn’t matter. 没关系。
Serves him right! 活该!
Looks like rain. 像是要下雨的样子。
Glad to see you. 很高兴见到你。
Hope to hear from you soon. 希望不久能接到你的来信。
Must have gone home. 准是回家了。
有时主语和助动词一起省略：
(Do you) Want some? (你) 要一点吗?
(Have you) Had a good time? 玩得好吗?
(We’ve) Got to go now. 得走了。
(I’m) Not feeling very well today. 今天感到不太舒服
(I’m) So pleased to have made your acquaintance. 认识了你很高兴。
(It’s) Nice day again. 又一个好天。