A:relied o
B:familiar with
C:turned to
D:based o
B: He's tall and strong.
用(How many\How much)的适当形式填空。
(Ⅰ)求证:A1B∥平面B1CD;
(Ⅱ)当三棱锥C﹣B1C1D体积最大时,求点B到平面B1CD的距离.