A:That's all right.
B:Sounds a good idea.
C:Sorry, I forgot it.
D:You're so kind.
如图所示几何体的俯视图是( )
一个圆锥形沙堆,底面直径8米,高3米,这个沙堆占地多少平方米?如果每立方米沙重1.5吨,这堆沙一共重多少吨?(π取3.14)