He came back late, _______ which time all the guests had already left.
| A．after | B．by | C．at | D．during |
You have failed two tests. You’d better start working harder, ____ you won’t pass the course.
| A．and | B．so | C．but | D．or |
—Did you return Fred’s call?
—I didn’t need to ____ I’ll see him tomorrow.
| A．though | B．unless | C．when | D．because |
Many children， ______ parents are away working in big cities，are taken good care of in the village.
| A．their | B．whose | C．of them | D．with whom |
____ parents say and do has a life-long effect on their children.
| A．That | B．Which | C．What | D．As |
—She looks very happy. She ______ have passed the exam.
—I guess so. It’s not difficult after all.
| A．should | B．could | C．must | D．might |