There are many mistakes in your homework. You should ______ special attention to the correct use of tenses.

Nice to see you. I _______ you for a long time.—–I _______ in Beijing, I’ve just come back.

Who is knocking at the door-It ______ be Mr. Wang. He always knocks at the door so loudly.

ment he came into his room, he ______ somethingwrong, though he couldn’t tell.

The young man was lying on thegrass with his horse _____a tree