Whose shirt is this—— It _______ be Li Lei’s. It is too big for him.

Hi, Vera, have you checked the account yet?— Certainly, I ______ it five times even though you told me to do it twice.[ ]

How is your English study— Not bad. But I learning English grammar.

So tired ___ after a whole day’s heavy work that I _____stand on my feet.

It is amazing that the little boy can swim ________the river ________100 meters in width