Solution: take PD midpoint G, PC midpoint H, even GF, FH. ∵ midpoint, ∴ GF ||| pH, GP||| FH, ∴ Pingsi PHFG, ∴ FGP = ∠ FHP. Even MG, NH: a, b, c and d are four * * * cycles, ∴ ADB = ∠ BCA, while: ∶rt△mpd, NPC, g and h are the midpoint of DP and PC respectively, ∴MG=DG, HN=HC, \ n * FHP = fgp, ∴∠MGF=∠NHF.* ∴fh=pg=mg Pingsi PHFG, RT△MDP, NPC, FG=PH=HN. At △MGF and △FHN, MG = FH, ∠MGF=∠FHN, GF = HN；; ∴△MGF≌△FHN,∴MF=FN。 In the same way, ME=EN, Zheng-shaped MENF, the certificate is over.