20. The prices of houses, ________ is often reported, have been going up sharply in

the past few months.

A. which　　 　　　　　　　　　 B. it　　　 　　　　　　　　　　　　 C. as　　　 　　　　　　　　　　 D. what

19. The city government is planning to build a factory to deal with the industry waste,

but hwen and where to build it _______. ☆考♂资♀源?网　　 ☆

A. haven’t been decided　　　 　　　　　　　　　　　　 B. aren’t decided

C. hadn’t been decided　　 　　　　　　　　　　　　　　 D. hasn’t been decided