Don’t bother me．I am listening to the birds ______．
| A．singing | B．sing | C．to sing | D．sung |
You have to be accurate in this job，because a small mistake can make a big ________.
| A．difference | B．difficulty |
| C．trouble | D．change |
They had their hearingby the loud noise of machines.
| A．injured | B．wounded | C．hurt | D．harmed |
My sister met him at the cinema yesterday afternoon, so heyour lecture.
| A．couldn’t have attended | B．needn’t have attended |
| C．mustn’t have attended | D．shouldn’t have attended |
——Will you stay for lunch?
——Sorry，. My brother is coming to see me.
| A．I mustn’t | B．I can’t | C．I needn’t | D．I won’t |
Seeing the enemy, Gary was behaving as though nothing.
| A．happened | B．had happened | C．would happen | D．was happening |