Social attention should be paid ________our earth from________.
| A．to preventing; being polluted | B．to prevent; polluting |
| C．to prevent; being polluted | D．to preventing; polluted |
________ my surprise, ________ I could have a word with him, he left.
| A．In; before | B．To; before | C．In; when | D．To; since |
The school ________I studied for only two years was three kilometers away.
| A．what | B．that | C．where | D．which |
After ________ hard, I got a job in a gold mine.
| A．to try | B．tried | C．trying | D．try |
It's helpful to put children in a situation ________ they can see themselves differently.
| A．that | B．when | C．which | D．where |
After visiting China，most of the foreign friends said they would never forget the time ________ they had spent in China.
| A．that | B．what | C．when | D．at which |