—Mum, where are my new socks?— How _______ I know? You’d better not put your things everywhere.
---Hi, Tracy, you looked tired.---I am tired. I______the living room all day.
______I understand your viewpoint, I don’t agree with it.
Do you know when the Great Wall _________?
He tried his best to solve the problem, _______difficult it was.
This film_________ the scenes of my childhood.