We can read the above material in . A. a newspaper B. a traveling report C. a textbook D.a job advertisement You can call if you’re interested in the special trips. A.Reader 2007 B.4,5&6 day breaks C.Italian Special Offers D.01223 434385 You 7.如图,正方形ABCD的边长为4cm,点P在边AD上以1cm/s的速度从点A向点D移动,(不与A、D重合),AE⊥BP,CF⊥BP,垂足分别为点E、F(如图1 ),(1)求证:FC=AE+EF;(2)过点P作PM∥FC交CD于点M(如图2 ),存在时刻t,使DM=2cm吗?若存在,求出时刻t;若不存在,请说明理由.(3)在(2)的条件下,何时线段DM最长,并求出此时DM的值.