－Did you see the hit New Year's movie-If You are The One（非诚勿扰）

last night!

－Yes, But when I got the movie theater, the film________ for ten minutes.[ ]

A. had begun      

B. had been on

C. had started      

D. begun

单作用曲轴式径向柱塞液压马达可分为（）和静力平衡式两种。