let down
1. 使失望
Don't worry. I'll never let you down.
别担心。我决不会让你失望的。
let in
1. 让……进来
Please open the window and let in some fresh air.
请打开窗透透新鲜空气。
let off
1. 宽恕
I'll let you off this time, but never again.
这次我宽恕你, 但以后不再宽恕了。
let on
1. 泄露秘密
Don't let on to her.
别向她泄露秘密。
let out
1. 泄露
Don't let out the plan to the press.
别把这计划泄露给新闻界。