Though his teachers were quite satisfied with his performance, he thought he ____ better if he had tried harder.
| A．could have done | B．should have done |
| C．ought to have done | D．must have done |
—Could you please have my car ready today?
—Sure, the damage is not that serious, so it ________ be ready by 5：00 pm.
| A．should | B．could |
| C．might | D．need |
The sleeping baby would be scared ________ a sudden loud noise.
| A．was there | B．there was |
| C．should there be | D．there should be |
—Mum, I'm tired.
—Well, if you ________ go to bed after midnight every night, what do you expect?
| A．will | B．may |
| C．should | D．can |
Brain, like muscles, also needs some kind of exercise and nutrition. The more you use your brain in the right direction, the more you ________ enhance your ability.
| A．could | B．might |
| C．shall | D．will |
We all know that we ________ our carbon footprint, but I suspect that many people wouldn't be prepared to go as far as Joan Pick, a retired scientist living in south London.
| A．must have reduced | B．should have reduced |
| C．may have reduced | D．could have reduced |