A:①②
B:②③
C:③④
D:①④
下列事例中,哪一个事不能表明物体的分子在不停地做无规则的运动( )
The air in Dongying is much worse than that in many other cities. We must do ______ to protect our environment.
选择下列适当的物质填空(选填序号):
A.干冰 B.火碱 C.聚氯乙烯 D.酒精 E.聚乙烯 F.稀硫酸 G.熟石灰 H.活性炭