In the environment area, there is a system ________ the waste is disposed of by using the principles of ecology.
| A．in which | B．which |
| C．on which | D．that |
--Why are your eyes so red? You _______ have slept well last night.
---Yeah, I stayed up late writing a report.
| A．can't | B．mustn't | C．needn't | D．won't |
When I was a child, I ______ watch TV whenever I wanted to.
| A．should | B．could | C．must | D．need |
I should not have laughed if I ______ you were serious.
| A．thought | B．would think | C．had thought | D．have thought |
He ________ sleep, although he tried to, when he got on such a hunt for an idea until he had caught it.
| A．wouldn’t | B．shouldn’t | C．couldn’t | D．mustn’t |
—Do you think George has passed the driving test?
—No. If so, he _____his car to our college yesterday.
| A．would drive | B．drove | C．would have driven | D．had driven |