题目

Our teacher asks us to clean the floor in the morning as our daily            . A．routine      B．virtue       C．scale    D．feature 答案：A如图，⊙O是△ABC的内切圆，切点分别是D、E、F，已知∠A＝100°，∠C＝30°，则∠DFE的度数是（   ）A．55°         B．60°      C．65°          D．70°