题目如图，AB为⊙O\odot O⊙O直径，弦CD⊥ABCD\perp ABCD⊥AB于E，OB=CD=2OB=CD=2OB=CD=2，则OE长为()(\quad)()A.1B.3\sqrt{3}3C.2D.5\sqrt{5}5知识点：垂径定理章节：未标注
如图，AB为直径，弦于E，，则OE长为如图，AB为直径，弦于E，，则OE长为如图，AB为直径，弦于E，，则OE长为