On the third floor there are two rooms, ____ is used as a meeting-room.
| A．one of them | B．the larger of which |
| C．and a larger of them | D．the largest one of which |
Many people believe we are heading for environmental disaster _____ we basically change the way we live.
| A．but | B．although | C．unless | D．once |
—Who _____ it be that is knocking at the door?
—It ______be father, but I’m not sure.
| A．can; may | B．may; can | C．may; must | D．need; should |
You can't imagine _____when they received these nice Christmas presents.
| A．how they were excited | B．how excited they were |
| C．how excited were they | D．they were how excited |
The meeting was of _____, and the information he offered at the meeting was_____.
| A．important; valuable | B．great important; of valuable |
| C．great importance; valuable | D．very important; of valuable |
The reason_______ his coming to China was _____ he wanted to study Chinese medicine.
| A．for, that | B．why, that | C．why, because | D．for, because |