A:圆柱
B:圆锥
C:球
D:正方体
-- I hear local people are trying to prevent some businesses building factories here.
-- Yes. They say the place may be polluted if some factories _______in the future.
(I)求证:DE∥平面A1C1B;
(II)求直线DE与平面ABB1A1所成的角的正弦值.