20、In the past three years, the Southeast Asian nation also witnessed its islands ____ by tsunami and typhoons．

A．being destroyed          B．destroying         C．destroyed          D．to be destroyed

19、So difficult _____ it to adjust to an English-speaking environment that he determined to learn English hard．

A．he has felt        B．has he felt         C．he did feel          D．did he feel

18、_____ better in 2010 World Expo is the duty of every citizen in Shanghai．

A．Being served         B．Serving            C．Serve         D．Having served

17、Look out ! Don' t get too close to the house __________ roof is under repair．

A．whose            B．which             C．of which          D．that

16、____ left before the deadline, it doesn’t seem likely that John will complete the job．

A．Although such a short time                         B．It is a short

C．With so short times                              D．With such short time

15、Advertising is distinguished from other forms of communication ______ the advertiser pays for the message to be delivered．

A．in that           B．in order that          C．in which         D．that

14、In which play of Shakespeare's is it ___ Viola appears?

A．where                    B．which                    C．who                   D．that

13、Nowadays business ______ on the Internet is growing rapidly, and this is a strong temptation for hackers, who are looking for ways to break into computer system．

A．having been done                          B．to have been done

C．to do                                           D．done

12、AIDS is said ______ the biggest health threat to both men and women in that area over the past few years．

A．being         B．to be          C．to have been          D．to being

11、We were disappointed to find that he was not _______ we had expected before．

A．as good a singer as                         B．as better a singer as

C．as a singer good as                       D．as a good singer as