取EC段为隔离体：ΣME =0,FC.3m -20KN.1m -0FC = 20/3 KN（向上）ΣMC =0,-FEy.3m +20KN.2m =0FEy = 40/3 KN（向上）ΣFx =0,FEx =0.取ADBE段为隔离体：FEy的反作用力FEy' =40/3KN（向下）ΣMA =0,FB.6m -(40/3KN)(7...