I have bought two books recently, but ________ interests my father.
| A．neither of which | B．neither of them |
| C．both of which | D．both of them |
The teacher is busy ____ correcting papers.
| A．for | B．in | C．on | D．of |
____ the problem of method is solved, talking about the task is useless.
| A．Until | B．Since | C．After | D．Unless |
Where have you been ____ you left home?
| A．before | B．as | C．since | D．when |
____ you told me, I had heard nothing of what happened.
| A．Till | B．Until | C．After | D．Since |
He ran off____ I could stop him.
| A．before | B．after | C．since | D．when |