_____ is our duty _____ the environment.
There used to be a lot of tall buildings,_________?
---Do you know ______famous tennis player named Li Na? ---Yes. She plays tennis well.
—The song Where did the time go ________ the old days and the love of family. —Sure. It’s my favorite song.
I don’t know with this problem.It’s too hard.
(原创)The coat on the bed _______more than 100 yuan.