There is no doubt the earth is becoming warmer.
| A．whether | B．that | C．if | D．why |
-Sorry, Mum. I got a C in the exam.
-You __________ have done better.
| A．would |
| B．must |
| C．could |
| D．shall |
-Can you keep a secret?
-You __________ worry-I'm not going to mention it to anyone.
| A．needn't |
| B．couldn't |
| C．mustn't |
| D．won't |
Just be patient. You __________ expect the world to change so soon.
| A．can't |
| B．needn't |
| C．may not |
| D．whether |
The door __________ open, no matter how hard she pushed.
| A．shouldn't |
| B．couldn't |
| C．wouldn't |
| D．mightn't |
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 |