我国采用光控晶闸管换流阀的工程为（）。
A.葛南
B.龙政
C.贵广
D.宜华
参考答案：C
The film ______ for 15 minutes by the time I got to the cinema. [ ]
A. had begun
B. had been on
C. has been on
由球面加工方法可知，铣刀回转轴线与球面工件轴心线的交角确定球面的（）
A.形状
B.加工位置
C.尺寸
D.粗糙度
