/let ||; lɛt/verb [T] (
present participle letting;past tense past participle let)
1 let sb/sth do sth to allow sb/sth to do sth; to make sb/sth able to do sth 准许；使…能做某事: My parents let me stay out till 11 o'clock. 父母允许我在外面待到11点才回家。I wanted to borrow Dave's bike but he wouldn't let me. 我想跟戴夫借自行车，可是他不肯。This ticket lets you travel anywhere in the city for a day. 有了这张票，你一天当中可以去这个城市的任何地方。
You cannot use let in the passive here. You must use allow or permit and to They let him take the exam again. He was allowed to take the exam again. Look at the note at allow. 这个义项，被动语态不能用let，得用allow或permit，再加上to：They let him take the exam again.他们允许他重考。 · He was allowed to take the exam again.他获准重考。参看allow的注释。2 to allow sth to happen 允许某事发生: He's let the dinner burn again! 他又把晚饭烧焦了！Don't let the fire go out. 别让火熄了。
3 used for offering help to sb （用于表示可给予帮助）: Let me help you carry your bags. 让我来帮你提袋子吧。
4 to allow sb/sth to go somewhere 允许…去某处: Open the windows and let some fresh air in. 打开窗，让新鲜空气进来。She was let out of prison yesterday. 她昨天获释出狱。
5 used for making suggestions about what you and other people can do （用于提出建议）让，任由: ‘Let's go to the cinema tonight.’ ‘Yes, let's.’ “我们今晚去看电影吧。”“好的。”
The negative is let's not or (in British English only) don't let's Let's not/Don't let's go to that awful restaurant again. 否定式是let's not，也可以是don't let's（限于英国英语）﹕Let's not／Don't let's go to that awful restaurant again.我们可别再到那家糟糕透顶的餐馆去。6 let sth (out) (to sb) to allow sb to use a building, room, etc in return for rent 出租（房屋、房间等）: They let out two rooms to students. 他们把两个房间租给学生。There's a flat to let in our block. 我们那座大厦有一套公寓出租。 ☞Look at the note at hire. 参看hire的注释。
let alone and certainly not 更不用说；遑论:
We haven't decided where we're going yet, let alone booked the tickets. 我们还未决定到哪里去，更不用说订票了。 let sb/sth go;let go of sb/sth to stop holding sb/sth 放开某人或某物:
Let me go. You're hurting me! 放开我，你弄得我好痛！Hold the rope and don't let go of it. 抓紧绳子，不要放手。 let sb know→
KNOW¹
let me see;let's see used when you are thinking or trying to remember sth （用于表示正在思考或回忆）让我想想:
Where did I put the car keys? Let's see. I think I left them by the telephone. 我把车钥匙搁到哪儿去了？让我想一想。大概就搁在电话旁边。 let sth slip to accidentally say sth that you should keep secret 无意中说出（秘密）
let's say for example 比如:
You could work two mornings a week, let's say Tuesday and Friday. 你可以每星期工作两个上午，比如说星期二和星期五的上午。 let yourself go 1 to relax without worrying what other people think 放松自己（无须担心别人的看法）: After work I like to go out with friends and let myself go. 下班后，我喜欢跟朋友出去，放松一下。
2 to allow yourself to become untidy, dirty, etc 不修边幅
let sb down to not do sth that you promised to do for sb; to disappoint sb 食言；使某人失望:
Rob really let me down when he didn't finish the work on time. 罗布没有按时完成工作，真叫我失望。 let on (about sth) (to sb) to tell sb a secret 把秘密告诉（某人）:
He didn't let on how much he'd paid for the vase. 他没有说花多少钱买了这个花瓶。 let sb off to not punish sb, or to give sb a less serious punishment than expected 饶恕某人；从宽处理:
He expected to go to prison but they let him off with a fine. 他本来以为要坐牢，但他们罚了他一笔款就放过了他。 let sth out to make a sound with your voice 发出声音:
to let out a scream/sigh/groan/yell 尖叫╱长叹╱呻吟╱大喊一声