一 Hi, Diana, how was your summer holiday?
一 ! I enjoyed myself in the sea very much.
( I)证明:AE⊥CD
( II)在棱ED上是否存在点M,使得直线AM与平面EFBD所成角的正弦值为 63 ?若存在,确定点M的位置;若不存在,请说明理由.
It takes us ________ hour to go there by ________ bus.