----What did Bob ask you just now?

----He wanted to know how long __________when I reached the cinema.

A．had the film been on

B．the film had started

C．the film had been on

D．had the film ended

酱油的卫生问题主要是______。

A．工业“三废”污染

B．化学性污染

C．微生物污染

D．昆虫污染