A:participate
B:participated
C:participating
D:to participate
如图,直线AB和直线CD交于点O,EO⊥CD,垂足为O,则∠AOE和∠DOB的关系是( )
如图,PAB、PCD为⊙O的两条割线,若PA=5,AB=7,CD=11,AC=2,则BD等于____