35. It is not yet well understood _______ has made the rainforest disappear year by year.

　　 A. what　　　　 B. which　　　　 C. that　　　　　　 D. how

34. Most of what has been said about the Browns _______ also true of the Dicksons.

　　 A. are　　　　　 B. is　　　　　　 C. being　　　　　 D. to be

33. --Hi, Johnson, l'm thinking of taking five courts in literature next term.

　 --Well, wouldn't four be __________?

　　 A. wiser　　　　 B. wise　　　　　 C. the wisest　　　 D. the wiser