A:旱涝
B:泥石流
C:地震
D:雪灾
如图.已知等腰梯形ABCD中,AB∥CD,AD=AB=12CD,M是的CD的中点.N是AC与BM的交点,将△BCM沿BM向上翻折成△BPM,使平面BPM⊥平面ABMD
(I)求证:AB⊥PN.
(Ⅱ)若E为PA的中点.求证:EN∥平面PDM.
读图:世界板块构造示意图,回答下列问题.
— It also happened to me. It brought back so many childhood memories.