不知道就问的英文

Any question please let me know.或者Tell me if any question.英语习惯跟中文习惯不同，他们会弱化问这个动作。比较直译的回答是：You can ask me for any question/advice.

if you don't understand,just ask

不懂就问。 Ask when you don't know.

If you don't understand, please ask.

Don't understand asked

Ask if you don't understand不懂就问