.
--- I hear you__________at Smith’s.
--- Yes, I__________there for about three months.
| A．work; had been working |
| B．worked; was working |
| C．are working; have been working |
| D．worked; have worked |
— She looks very happy. She __________ have passed the exam.
— I guess so. It’s not difficult after all.
| A．should | B．could |
| C．must | D．might |
The biggest problem for most plants, which ___ just get up and run away when threatened, is that animals like to eat them.
| A．shan’t | B．can’t |
| C．needn’t | D．mustn’t |
In crowded places like airports and railway stations, you __________ take care of your luggage.
| A．can | B．may |
| C．must | D．will |
The teacher __________ have thought Johnson was worth it or she wouldn’t have wasted time on him, I suppose.
| A．should | B．can |
| C．would | D．must |
The weather turned out to be fine yesterday. I __________ the trouble to carry my umbrella with me.
| A．should have taken | B．could have taken |
| C．needn’t have taken | D．mustn’t have taken |