. China won 100 medals in the Beijing Olympic Games, which are almost ______ those of the Sydney Olympic Games.
| A．twice as many as | B．as many as twice |
| C．as much as twice | D．twice as much as |
Only when David did it a second time _________.
| A．he realized his mistake |
| B．he was realizing his mistake |
| C．did he realize his mistake |
| D．he did realize his mistake |
So instructive _________ that the student wanted to see it again.
A. was the film B. it was the film
C, the film was D. the film it was
Not until I went to America _________ what kind of country it was.
| A．did I know | B．I did know |
| C．I didn't know | D．I could know |
_________ forget my hometown and my happy childhood.
| A．Never I will | B．Never will 1 |
| C．Never I | D．I never have |
_________ she would have avoided the accident.
| A．She was more careful | B．If she was more careful |
| C．Had she been more careful | D．She had been more careful |