1.let sb. in on sth. 要告诉某人一个秘密或讯息（很少人知道的）

　　I'll let you in on a little secret –Sarah only got the job because she's dating the boss' brother.

　　我要告诉你一个小秘密，Sarah能得到那份工作是因为他跟老板的兄弟在约会。

　　2. let's shake on it 协议达成；一言为定；那就这么合作吧

　　“How much for your bike?”

　　单车多少钱？

　　“$200.”

　　两百美元。

　　“I'll give you $100 for it.”

　　我出一百美元。

　　“How about $150?”

　　一百五十美元怎么样？

　　“All right. Let's shake on it.“

　　好的，一言为定。

　　3. letit slide 不要在意这些小问题

　　I made some punctuation mistakes inmy essay, but the teacher let it slide – she didn't take any points off.

　　我在文章中犯了一些标点符号的错误，但是老师没有在意这些问题 － 她没有指出来。

　　4. let it go = let go 让它过去；放手；不再为此纠结

　　I was angry about what she did for along time, but eventually I decided to let it go.

　　我原本对她很生气，但是最后决定让它过去。

　　5. let it be 顺其自然

　　“I'm not sure the oven is hot enough… maybe I should turn up the temperature.”

　　我不确定炉子是不是够热...也许我应该升高温度。

　　“Just let it be – the chicken is supposed to cook slowly, on low heat.”

　　顺其自然吧，炖鸡就低温应该慢慢煮。

　　6. let your guard down 放下你的防备

　　“After a series of terrible relationships, I was finally able to let my guard down after I got to know my husband.”

　　在经过一些糟糕的恋爱经历后，我认识了我丈夫，终于我能够放下了我的防备。

　　7. let's call it a day 今天就到此为止；今天的工作结束了。

　　We've already packed 30 boxes. I'm tired – let's call it a day.

　　我门已经打包了30个盒子。我很累了，今天就这样吧。