实验室应保持整洁有序，不准喧哗、打闹、抽烟。
参考答案：对
排序。
( ) I'd like some books.
( ) What book would you like?
( ) Can I help you?
( ) Here are some book on music.
( ) Some book on music.
( ) Sure.
区分人类历史上不同社会形态的根本标志是( )。
A．社会文明水平 B．社会经济制度C．市场发达程度 D．科技发展水平
