As we all know.____life is hard for any of us. If we live___ happy life,we must all work harder.
One of the sides of the board should be painted yellow, and ______. .
---You don’t often see them, do you? ---No, I see ______of them.
He is clever and hard-working, so he has _____ reason to succeed in the exam.
It’s ______, as I trust you so much.
One of the students hasn’t prepared ____ lessons very well.