语法与词汇 Noise in a room may be reduced by carpeting,draperies, and upholstered furniture, _____ absorb sound.

【正确答案】 C

【答案解析】句意：房间里的地毯、布料和软垫家具都可以减少房间的噪音，他们都能吸收声音。 all of the furniture，这里which在定语从句中作关系代词，代指furniture。