Q: What would you like to play or What do you want to play with? Which one is more natutal to say to kids? は 英語 (アメリカ) で何と言いますか?
A: "What would you like to play?" is the best because it could be basically any game, even something like rock-paper-scissors or some kind of a verbal guessing game.
"What do you want to play with?" would be used specifically to mean "Which toy do you want?"


Q: 形容女人没有整容(no facelift)100%纯天然。100% pure natutal この表現は自然ですか?
A: I'd say "she's a natural beauty" or "her beauty is 100% natural". If you want to just say she didn't have plastic surgery, you can say "she hasn't had any work done" or "she hasn't had plastic surgery"
Q: That's too small to me.
That's too small for me.

Which sounds natutal? この表現は自然ですか?
A: the second one
Q: I think it's natutal to say "Let me explain it". But when the person who wants to explain is "we" not only "me", can I say "Let us explain it"? Please have a image that you're the representative of a company and saying an opinion as a company not a person.
Anyway, if you noticed unnatural expression on this question itself, please point it out also! この表現は自然ですか?
A: "Let us explain it" seems logical but not in the situation you are giving. For some reason, that sounds like a command.

If I was in a meeting or so trying to explain something for the company, I'd say "We are going to explain it".

Actually, "Allow us to explain it" would be better.

Errors on question:
*natural (i know this is a typo but just in case ^^)
*an image
*and you're saying an opinion for the whole company, not just yourself.
Q: A is normal. と A is common. と A is natutal. はどちらが自然ですか?
A: QAの全文をご確認ください