This is the only one of the books on space ___.
| A．that has been written | B．that have been written | C．which have been written | D．which has been written |
—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 |
When I lived with my roommates in the university, we ________ often talk into the night.
| A．might | B．could |
| C．should | D．would |
________ 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 |
You ________ in person; a telephone would have been enough.
| A．couldn't have come | B．needn't have come |
| C．shouldn't have come | D．mustn't have come |
I felt surprised that anyone of his intelligence ________ such an easy test.
| A．might have failed | B．could have failed |
| C．should have failed | D．must have failed |