如图,⊙O的直径BA的延长线与弦DC的延长线交于点E,且CE=OB,已知∠DOB=72°,则∠E等于( )
A:36°
B:30°
C:18°
D:24°
If you see any litter on the school playground, you'd better _______.
创新没有捷径,先有“厚积”,而后才能“薄发”。这启示我们