A:方便车、马、行人通过
B:减小水的冲力、节省材料、减轻桥的自重
C:美观
D:有个性
The Tang costume is very ____ (attract) and very different from western-style suits.
在4Al+3O22Al2O3中, ____ 份质量的铝和 ____ 份质量的氧气反应,生成 ____ 份质量的三氧化二铝.各物质质量比为____ .