The teachers always complain about the children in class.
| A．to teach, tired | B．teaching, tired |
| C．teaching, tiring | D．to teach, tiring |
We should do everything we can the environment .
A. to protect B. protectC. protecting
______of the earth ______ covered by water.
A. Two thirds; is B. Two thirds; are C. One thirds; is
If we travel a short distance, we had better walk taking a bus.
A. instead B.instead of C. take the place of
The wind is blowing strongly with lots of sand, so I can’t see _______.
A. nothing B. something C. anything
--- I usually have breakfast at home. ---- ________ .
A. So have I B . So do I C.So I do