约占细胞总量的97%的元素是[ ]
A．C、H、O
B．Co、I、Mn、Fe
C．C、H、O、Cu、N
D．C、H、O、N、P、S
答案：D
－I don’t know
－Because he has to look after his mother.
A．Why he is leaving
B．why is he leaving
C．whether he will leave
D．what is he leaving for
《公共场所卫生管理条例》规定的文化交流场所是（）
A.咖啡馆
B.KTV包厢
C.公园
D.博物馆
E.音乐厅
