—Did you enjoy yourself last night?—Yes, it’s very nice of you. I appreciated to the party.
Rather than _____on a crowded bus, he always prefers _____a bicycle.
---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.