__________ the program , they have to stay there for another two weeks.
| A．Not completing | B．Not having completed |
| C．Not completed | D．Having not completed |
World Wildlife Fund ______ very much the efforts that China has made to protect endangered species from being further endangered.
| A．enjoys | B．appreciates | C．thanks | D．prefers |
It’s wise to forget things which aren't worth ______.
| A．being remembered | B．remembering | C．to be remembered | D．to remember |
With the fast development of computer and Internet technologies, traditional printed books ______ by the growing popularity of online reading of e-books.
| A．are challenged | B．have challenged |
| C．are being challenged | D．have been challenged |
In many people’s opinion, that company, though relatively small, is pleasant ______.
| A．dealt with | B．dealing with | C．to be dealt with | D．to deal with |
The computer system _____suddenly while he was surfing the Internet.
| A．broke up | B．broke out | C．broke in | D．broke down |