Alex: Why are you still here?  It’s almost eight o’clock.  Tom: Because I 　　　 my work. 

Don’t worry.  It’s almost done.

A．wasn’t finishing

B．wouldn’t finish

C．haven’t finished

D．won’t finish

HCF80装盘机空盘台上传送轨向前输送空盘和退回原位的远动由（）轮机构驱动。

A.齿

B.链

C.带

D.凸