—Has William finished writing his graduation paper yet?
—I don’t know exactly，but he __________all day.
| A．is writing | B．has been writing |
| C．was writing | D．wrote |
Leave your key with a neighbor _______ you lock your-self out one day.
| A．ever since | B．even if |
| C．soon after | D．in case |
I got caught in the rain and my suit _______.
| A．has ruined | B．had ruined |
| C．has been ruined | D．had been ruined |
You have failed two tests.You’d better start working harder,_______ you won’t pass the course.
| A．and | B．so | C．but | D．or |
The new group of students is better-behaved than the other group who stayed here _____.
| A．early | B．earlier | C．earliest | D．the earliest |
He is a student at Oxford University,_______ for a degree in computer science.
| A．studied | B．studying |
| C．to have studied | D．to be studying |