of the land covered with forests.
| A．Two thirds; is | B．Two thirds; are |
| C．Two third; is | D．Two third; are |
_____ he is only 4 years old，he is able to play the piano very well．
| A．if | B．although | C．unless | D．until |
Working hard ________ the key _________ success of everything．
| A．is,to | B．is,of | C．are,in | D．are,for |
We feel like ___________ the work as soon as possible．
| A．finish | B．to finish | C．finishing | D．finished |
The old man lives _______ in the countryside, but he didn’t feel __________．
| A．lonely；alone | B．alone；lonely |
| C．alone；alone | D．lonely；lonely |
He didn’t know English at all, so he can’t understand __________ the machine．
| A．what to control | B．to control what |
| C．how to control | D．to control how． |