You must have read about Mark Twain long ago, ____?
| A．mustn’t you | B．haven’t you |
| C．didn’t you | D．needn’t you |
I think only when he attends college _______________ more independent of his parents.
| A．will he become | B．he becomes | C．he will become | D．becomes he |
Using his hybrid rice, farmers are producing harvests ________________ before.
| A．as large twice as | B．twice as large as |
| C．twice larger as | D．as large as twice |
The situation is getting worse. We must __________ the trouble _____________.
| A．keep; spreading | B．prevent; spreading |
| C．stop; to spread | D．protect; to spread |
___________ was no doubt __________ someone had broken into the store the day before.
| A．There; that | B．There; whether | C．It; that | D．It; whether |
You __________ have told him my comment on him. Now, he is very angry with me.
| A．needn’t | B．couldn’t | C．shouldn’t | D．mustn’t |