So don't you let me down.

请你莫负我心痴。

youdao

Put the game box down, ……don't let me catch you.

把…游戏盒…留下…不要…让我抓到你们…（上气不接下气的样子）

youdao

I'd like you to do this for me. Don't let me down.

我希望你能为我做这件事。不要让我失望。

youdao

Do they come up with excuses in the middle of a conversation to pull out their smart phone -- something like "let me jot something you said down so I don't forget it, " and then sneak a look at all their messages?

WSJ: Addicts of the Information Age