— The teacher asked us ________________
A. What the bad effect of pollution are.
B. What were the bad effect of pollution.
C. What the bad effect of pollution were.
I wonder what you mean __________ saying that?
| A．for | B．by | C．with | D．to |
“Remember not ______ your homework at home again,” said the teacher.
| A．leave | B．to leave | C．forget | D．to forget |
Our Earth will be ________ if we go on cutting down millions of trees every year.
| A．in great danger | B．danger | C．dangerously | D．out of danger |
Trees provide food and shelter and make us ______ comfortable.
| A．feeling | B．feel | C．feels | D．felt |
Trees make our city more beautiful and ________ noisy, do you think so?
| A．much | B．little | C．less | D．fewer |