His singing career began to ______ in the late 1990s.
| A．get off | B．take off |
| C．put off | D．set off |
---Mr. Smith must know a lot about Chinese history.
---________. He has studied it for years.
| A．So he does | B．So does he | C．So he must | D．Yes, he must |
While watching television, ________.
| A．the doorbell rang | B．the doorbell was rung |
| C．we heard the doorbell ring | D．we heard the doorbell rings |
In our factory there are 2,000 workers, two thirds of _______ are women.
| A．them | B．which | C．whom | D．who |
Your decision will affect your future study in college and your future job _______.
| A．as though | B．as if | C．as well | D．as well as |
Mr. Smith likes traveling _______; but his wife enjoys _______.
| A．by train; taking a taxi | B．on train; by taxi |
| C．by train; by taxi | D．on train; taking a taxi |