下列物质,属于纯净物的是 [ ]
A.空气
B.石油
C.酒精
D.石灰水
答案:C
(2013·湖南高考)Around two o'clock every night, Sue will start talking in her dream. It somewhat ________ us.
A.bothers
B.had bothered
C.would bother
D.bothered
土地的功能不包括( )。
A.人类生存的物质基础
B.人类生存的社会基础
C.人类生产的场所
D.人类生活的场所