31. The decision ______ Internet addiction（成瘾）as a mental disorder has caused much debate.
| A．to classify | B．classifying |
| C．being classified | D．to be classified |
He wrotesong, which turned out to be rather popular withyoung.
| A．a; the | B．a; a | C．the; a | D．the; the |
-----What upsets him?
-----_____ his computer is out of order．
| A．Whether | B．What | C．That | D．How |
— Frank, I’ve learned your plan. Could I make some suggestions?
— ________.
| A．Just for fun | B．Go ahead | C．With pleasure | D．Take it easy |
We are kept ______ of what is happening in the world by reading newspapers and watching TV.
| A．to inform | B．to be informed | C．informing | D．informed |
The time and effort he has devoted during the past few years _____ trees in that village are now considered to be very important.
| A．to planting | B．to plant | C．plant | D．planting |