________ your letter, I would have set off two days ago.

A．If I could have received

B．Should I receive

C．If I received

D．Had I received

When I lived with my roommates in the university, we ________ often talk into the night.

A．might B．could

C．should D．would

—Where did you get The Frog written by Mo Yan?

—I picked it up from a bookshop online if you ________ know.

A．must B．will

C．can D．shall

Every time she was in trouble, she went to him for help, as he said he ________ do anything for her.

A．should B．must

C．would D．might

________ me what you wanted to know, I should not have wasted my time talking so much with you.

A.Had you toldB．You have told

C．You had toldD．Have you told

I wrote a letter to John for his help during my high school years，without which I ________ the college entrance exam.

A．would fail B．would have failed

C．should fail D．must have failed

—Did Ann fail in English?

—She ________. Don't you notice that she looks depressed?

A.might B．must

C．may have D．could have

Students ________ remain in their seats until all the papers have been collected.

A．wouldB．shall

C．will D．could

She didn't come to the party last Sunday. ________， she must have made the party more exciting.

A．If she came B．Would she come

C．Had she come D．Did she come

I know that it will be difficult to pick him out in such a crowd, but if you ________ happen to see him, give him this packet.

A.wouldB．might

C．shouldD．could