We want to encourage the students ________ the teaching.
| A．to participate in | B．participate in |
| C．participating | D．participate to |
The reason for his success is ______ he worked very hard.
| A．why | B．that | C．whether | D．how |
______ anyone should want to kill her was unbelievable.
| A．Whether | B．That | C．What | D．If |
The government has to close those small factories to prevent the water of the river ______.
| A．polluting | B．from polluting | C．being polluted | D．polluted |
He wants to see changes in the company and I am sure he will, ______.
| A．on time | B．at a time | C．at one time | D．in time |
We should try our best to ______ those people after the disaster.
| A．break out | B．cheer on | C．break up | D．cheer up |