— Who _____ be phoning us at this time of night?
— It might be your sister.
| A．might | B．can | C．dare | D．must |
. Is this school _______ some German friends visited last week?
| A．the one | B．where | C．that | D．which |
I have to turn to my teacher for help, because this math problem is rather difficult______.
| A．worked out | B．to be worked out | C．working out | D．to work out |
They desired that they __________ the right to attend the meeting.
| A．had | B．have | C．has | D．were |
They talked a lot about the things and persons ________they saw in the Vancouver Winter Olympics.
| A．which | B．that | C．whom | D．what |
We didn’t know you were in trouble at that time, _______ we would have given you a hand.
| A．while | B．when | C．therefore | D．otherwise |