________ the arrival of the police, I would have been robbed by two masked men.
A．Had it not been for B．If it were not for
C．Had it been not for D．If it would not be for
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
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
Students ________ remain in their seats until all the papers have been collected.
A．wouldB．shall
C．will D．could
—Did Ann fail in English?
—She ________. Don't you notice that she looks depressed?
A.might B．must
C．may have D．could have
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
