______in a proper way, waste can be turned into useful things.
| A．To deal with | B．Dealt with | C．Dealing with | D．Being dealt with |
You shouldn’t keep silent when __________．
| A．speaking | B．spoken to | C．spoken | D．speaking t |
---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 |
Though he is __________ worker, he works very hard.
| A．a common | B．an ordinary | C．a usual | D．a general |