A.分子间存在引力
B.分子间存在斥力
C.分子间有间隙
D.物质间有扩散现象
答案:A
The teacher noticed him ________basketball on the school playground a moment ago.[ ]
A. played
B. to play
C. playing
D. was playing
()是指一份表格上只登记一个调查单位有关调查项目的调查表。