—Are you still busy?

—Yes，I________my work，and it won't take long.

A．just finish

B．am just finishing

C．have just finished

D．am just going to finish

黑肢病的原因是（）。

A.慢性砷中毒

B.慢性氟中毒

C.慢性镉中毒

D.慢性甲基汞中毒

E.严重碘缺乏