She suggested the problem worth paying attention ________ at the meeting.
| A．to be discussed | B．to been discussed |
| C．to being discussed | D．should be discussed |
______time went on, the people in the area came to realize how serious the environment had been polluted.
| A．As | B．With | C．When | D．While |
I didn’t manage to do it______you explained how.
| A．until | B．unless | C．when | D．before |
.Don’t stop______you meet with a word you don’t understand.
| A．at that time | B．each time |
| C．sometimes | D．when every time |
Don’t be afraid of asking for help ______it is needed.
| A．unless | B．since | C．although | D．when |
He made a mistake, but then he corrected the situation ______it got worse.
| A．until | B．when | C．before | D．as |