25. The environment is heavily polluted ____ its economy is quickly developed.

A. at which　　　　　 B. where　　　　　 C. which　　　　　 D. to which k+s-5#u　

24. If _______, the disease may become deadly.

A. to be treated　　　　　 　 B. not being treating　 C. not treating　　 　 D. untreated

23. _____ seems strange to us is_____ she can sing so many English songs beautifully.

A. What; that　　　　　　 　 B. It; why　　　　 　 C. That; how　　　　　 　 D. It; that

22. One of the students held the view _______ the teacher said was wrong.

　 A. that　　　　　　 B. what　　　　　　 C. that what　　　 D. what if

第一节：单项填空(共15小题，每小题1分，满分15分)

21. Democratic Party candidate Barack Obama(奥巴马), who is ______ African American was elected ______ president of the United States.　　　　

A. the; /　　 　　　　　 　B. an; a　　 　　　　　　 　C. the; the　　　　 D. an; /