how should i answer
if some one said: any question?
what should i say if there is no question in my mind.

Question

Answer

If someone says "Any questions?" and you have no question in your mind, you can say many things. To be abrupt you can just say "No", but to be more friendly or polite you can say "No, that's very clear, thank you". or
"None, I'm happy with that, thanks". or "Not at the moment, but if I think of any I will ask later". or just "no, but thank you".
Your answer can be quite flexible.

Answer

You can also say 'none at the moment, thanks!' 

'No everything 's clear so far, thanks'

Answer

yoo     should       said    ： Mm......