A competent speaker of a language must have a(n)________ of these different styles.
| A．comment | B．observation | C．command | D．response |
People planted trees on the waste hills_________ water and soil loss.
| A．to decrease | B．decreasing |
| C．decreased | D．decrease |
Judging from his accent, he_______ be from Australia.
| A．needn't | B．mustn't | C．can't | D．wouldn't |
-Can we sit at the table by the window? -I'm sorry, but it_______ already
| A．has taken | B．has been taken |
| C．was taken | D．took |
They reached the top of the mountain__________ they could see the highway wandering before them.
| A．which | B．why | C．whose | D．where |
______ in the training, Marbury couldn't play in the basketball season.
| A．Injuring | B．Injure |
| C．Injured | D．To injure |