His friends found to tell him everything that had happened.
| A．it necessary | B．that necessary |
| C．it is necessary | D．necessary |
“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 |
Three trees can do the job of 15air-conditioners _________ almost all day.
| A．run | B．are running | C．ran | D．running |