题目如图,l1l_{1}l1∥l2l_{2}l2∥l3l_{3}l3,根据"平行线分线段成比例定理",下列比例式中正确的是( )A.ADBC=CEDF\frac{AD}{BC}=\frac{CE}{DF}BCAD=DFCEB.ADBE=BCAF\frac{AD}{BE}=\frac{BC}{AF}BEAD=AFBCC.ABCD=CDEF\frac{AB}{CD}=\frac{CD}{EF}CDAB=EFCDD.ADBC=DFCE\frac{AD}{BC}=\frac{DF}{CE}BCAD=CEDF知识点:平行线分线段成比例章节:未标注