— Beibei, is Mr. Chen in the office?

— No. He        for half an hour.

A. left                   

B. has left           

C. has been away

内容不违反法律的明文规定但是损害社会公共利益的民事行为_______。

A．有效
B．绝对无效
C．相对无效
D．可变更、可撤销