—Here's the film to be developed. I need the pictures in 15 minutes.

—OK. But you have to pay extra _____.[ ]

A. offer  

B. charge    

C. wage        

D. salary

风力发电机组机械系统由（）组成。

A.主轴、齿轮箱和联轴器

B.制动器、叶轮、浆距控制器、偏航驱动器

C.机舱

D.发电机