The dictionary is of great use to me. I would gladly have paid       for it.

A．twice as much

B．twice as many

C．much as twice

D．many as twice

一个圆柱体的体积增加6立方厘米，那么与它等底、等高的圆锥体的体积就应增加[ ]

A．2立方厘米    

B．3立方厘米  

C．4立方厘米  

D．6立方厘米