Never _______ protecting our earth. It is the only nice planet for us to live on.
| A．leave for | B．learn about | C．give up | D．look up |
There is _____ pollution in the world. We must stop it.
| A．much too | B．too many | C．many too | D．too much |
The cleaners must prevent the street ______.
| A．getting dirty | B．from dirty | C．from get dirty | D．from getting dirty |
None of us _____ running, but we all like swimming.
| A．likes | B．liked | C．liking | D．would like to |
He is tall, _____ his son is short.
| A．when | B．or | C．while | D．and |
What can we students do _____ the environment?
| A．to protect | B．protected | C．protecting | D．protects |