If you can't come, leave a note in my pigeonhole.

你若不能来，在我的信件格里留张便条。

《牛津词典》

If mom can't be home when kids get back from school, she can leave a note with a voice and picture on the screen to tell them what there is to eat.

如果孩子们从学校回来时妈妈不能在家，她可以在屏幕上用声音和图片留下便条，告诉他们有什么吃的。

youdao

Seeing nobody at home, he decided to leave a note.

看到没人在家，他决定留下一个便条。

youdao

We leave a note asking a simple question: What's in those unmarked boxes?

FORBES: Magazine Article

But if there's anyone out there who has made it happen and wants to share their revelation, why not leave a note below?

ENGADGET

He didn't leave a note.

NPR: Danny Gatton: 'World's Greatest Unknown Guitarist'