题目如图,在⊙O\odot O⊙O中,弦ABABAB∥CDCDCD,点EEE在AD^\widehat {AD}AD上,延长EDEDED至点FFF,使EF=EBEF=EBEF=EB,延长AEAEAE至点GGG,连结GFGFGF,使∠F=∠EAC\angle F=\angle EAC∠F=∠EAC,GF=ADGF=ADGF=AD.(1)(1)(1)连结CBCBCB,求证:GF=CBGF=CBGF=CB;(2)(2)(2)若∠F=70∘\angle F=70^{\circ}∠F=70∘,CACACA为⊙O\odot O⊙O直径,求∠ABE\angle ABE∠ABE的度数;(3)(3)(3)连结BDBDBD,求证:∠G=∠BDE\angle G=\angle BDE∠G=∠BDE.知识点:垂径定理章节:图形的性质 / 圆