房地产投资风险中的动态风险，可通过（ ）加以规避。
A．经营者自身努力
B．加强对投资项目的评估
C．投保
D．防止意外事故发生
参考答案：A
We have heard of many cases _______ some citizens ，especially some famous people， have suffered because personal information had been leaked.
A．why
B．which
C．as
D．where
若有如下二叉树，则对此二叉树前序遍历的结果为( )。
