Pollution is a serious problem. Scientists have _______ some good ways to save it.
| A．come up with | B．come on | C．come out | D．come up |
By the time I got back to school, the bell______.
A. rang B. has rung C. had rung
He has never been to Beijing, ______?
A. hasn't he B. has he C. doesn't he
—Would you like ______ cake?
—Thanks, but I'm full.
A. another B. other C. the other
Sandy likes the actors ______ are popular among teenagers.
A. who B. which C. whom
—Han Hong ______ by the reporter yesterday.
—She's great. She helped so many disabled people.
A. was interviewed
B. is interviewed
C. is interviewing