—Alison, I'm sorry. I can't come to the wedding with you tomorrow morning.

—________?

—My grandma was severely ill, so I have to stay in the hospital to look after her.[ ]

A. How is it  

B. How come

C. So what  

D. What's the problem

师生关系从本质上讲是一种（　）。

A．人一物关系

B．授一受关系

C．道德关系

D．人一人关系