________ the police thought he was the most likely one，since they had no exact proof about it，they could not arrest him.
| A．Although | B．As long as |
| C．If only | D．As soon as |
There was a lot of fun at yesterday's party. You________come, but why didn't you?
| A．might have |
| B．should |
| C．must have |
| D．ought to have |
—John, how did your maths exam go?
—I thought I________， but in fact I came in the top ten in the class.
| A．should have failed |
| B．couldn't have failed |
| C．might have failed |
| D．mustn't have failed |
As you worked late yesterday, you________have come this morning.
| A．mayn't |
| B．can't |
| C．mustn't |
| D．needn't |
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 |
—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 |