如图是核反应堆的示意图，对于核反应堆的认识，下列说法正确的是（ ）
从方框中选择恰当的语句，补全对话。
A.Yes, she is.
B.He's my brother.
C.No, he isn't.
D.He's my brother.
Cheng Jie: Who's that boy?
Amy:____
Cheng Jie: Is she your mother?
Cheng Jie: Is he your father?
如图，AB是⊙O的弦， OC⊥AB于点D，交⊙O于点C，若⊙O的半径为10，CD＝4，那么AB的长为（ ）
