What’s the meaning of “by mistake?”—It’s “____”. [ ]

Why are you in such a hurry, Meimei? -The fashion clothes are sold in the supermarket at the moment?

I think teenagers shouldn’t be allowed to smoke.－I agree ______ you.[ ]

_______is your new teacher like? —–Friendly and polite.

It _______ seven years __________ Hong Kong returned to China.