A:①②④
B:③④⑤
C:②④⑤
D:①②③
如图所示,在直三棱柱ABC﹣A1B1C1中,AB=BC=BB1,D为AC的中点.
(I)求证:B1C∥平面A1BD;
(Ⅱ)若AC1⊥平面A1BD,求证:B1C1⊥平面ABB1A1;
粮站运来面粉和大米各200袋,运来面粉和大米一共____千克?