— Mum, why do you give me so much popcorn?

— _____ the boring time.

A．Kill

B．Killing

C．To kill

D．Having killed

大学生买火车票不仅可以打折，还可以在候车室等车。而民工不但不可以打折，还要在广场顶风冒雨等车，你怎么看