(1)AB=3EH;CG=2EH; 3/2.(2)m/2 作EH∥AB交BG于点H,则△EFH∽△AFB∵AB/EH=AF/EF=m ∴AB=mEH∵EH∥AB∥CD,∴△BEH∽△BCG.∴CG/EH=BC/BE=2 ∴CG=2EH∴CD/CG=mEH/2EH=m/2(3)ab【提示】过点E作EH∥AB交BD的延长线于点H.