下列变化中，属于化学变化的是 [ ]

A. 水沸腾变为水蒸气　　　

B. 石蜡熔化

C. 工业上用空气为原料制氧气 　　　　

D. 钢铁生锈

— You aren't a student now, are you?

— _____, don't you remember _____ me in the classroom ten minutes ago?[ ]

A. No; seeing        

B. Yes; seeing            

C. No; to see