如图,AD是△ABC的中线,E,F分别是AD和AD延长线上的点, 且DE=DF,连接BF,CE.下列说法: ①CE=BF; ②△ABD和△ACD的面积相等; ③BF∥CE; ④△BDF≌△CDE.其中正确的有( )A.1个 B.2个 C.3个 D.4个 答案:D________others whenever you can,and you will make the world a nicer place to live in. A.Help B.Helped C.To help D.Helping