—_____ the population of the U.S.A. in 2005?
—It _____ about 296 million.
A.What is; is B.What was; was
C.How many is; was D.How many was; is
Students should do everything they can __their study.
| A．improve | B．to improve |
| C．improving | D．improved |
If you are a little careful, I think you can _____the problem.
| A．get over | B．get in | C．get on | D．get off |
Joan writes ____than she did 2 years ago.
| A．much more careful | B．more careful |
| C．much carefully | D．more carefully |
—The pollution problem here seems to get more and more serious.
--Yes. Something_____about it.
| A．must do | B．must be done |
| C．is doing | D．had been done |
When I got to the cinema, the movie ___for 15 minutes.
| A．began | B．had been on |
| C．had begun | D．has begun |