.I can never forget the day ______ we worked together and the day _______ we spent together.
| A．when; which | B．which; when | C．what; that | D．on which; when |
We will lose the game unless he ______ us.
| A．helps | B．helped | C．was helping | D．has helped |
Ladies and gentlemen, please fasten your seat belts. The plane ______ in five minutes.
| A．is about to take off | B．is taking off | C．takes off | D．was taking off |
---The meeting has begun and __________ he will come.
---Of course, he is sure to come. He’ll speak at the meeting.
| A．I believe | B．I hope | C．I think | D．I doubt if |
—What do you think of this matter? —This is a matter of__________ importance. I think.
| A．especial | B．quiet | C．rather | D．special |
Some countries are increasing their use of natural gas, and other forms of __________.
| A．source | B．energy | C．power | D．material |