29. New ways _____ to prevent the river _____.
| A．have found out, from polluting |
| B．have found, from being polluted |
| C．have been found out, from being polluted |
| D．have been found, from being polluted |
30．______ the news that her son was still alive, tears rolled down the old woman’s face.
| A．Hearing | B．heard | C．Having heard | D．When she heard |
29．It will lead to very serious result if this matter was ______ unsolved.
| A．stayed | B．remained | C．left | D．Keeping |
28．I didn’t enjoy the party very much. I knew ______ nobody there.
| A．hardly | B．nearly | C．almost | D．Mainly |
27．After the adventure, the children returned home, ______.
| A．safe but tired | B．safely but tiredly |
| C．safely but tired | D．safe but tiredly |
26．— Do you have any idea what Paul does all day?
— As I know, he spends at least as much time playing as he ______.
| A．writes | B．is writing | C．does writing | D．does write |