Let me know if you have any problems.

你若有困难就告诉我。

《牛津词典》

If you should change your mind, do let me know.

假如你改变主意的话，一定要告诉我。

《牛津词典》

Let me know if you run into any snags.

要是遇到什么麻烦就告诉我。

《牛津词典》

They receive permission and open fire on the group. "Let Me know when you've got them."

VOA: standard.2010.04.06

Now we're going to see a bunch of examples and I know those are words, let me give you an example.

让我们来看看例子吧,我知道那只是概念，来看个例子。

麻省理工公开课 - 计算机科学及编程导论课程节选

you say, "Okay, there's this party but let me know what you think."

你说，“好的，今晚有个派对。你想不想去？”

Let me 课堂 - SpeakingMax英语口语达人

And he was good-natured about it and said, can't you just keep one, one case for me, so that when I come in - and I said, I tell you what, you let me know when you're coming in and I'll run across the street and buy you a bottle of flat still water and have it on your table.

NPR: At Chez Panisse, It's Time for Tap Water

And so my therapist, you know, psychologist was taking me around, trying to just, you know, dip me in a little bit to let me know, you know, this is the business here that you've been in all your life.

NPR: Etta James: Still Singing Her Song

Whether you agree with the article or not, let me know what you think.

BBC: "The reluctant dragon" - The Economist reports on Wales