His new neighborhood     _ very quiet, but now it's very noisy.              [ ]

A. was used to be    

B. used to      

C. is used to        

D. used to be

十字头销外圆表面的缺陷采用（）方法检查。

A．观察

B．着色探伤

C．磁粉探伤

D．超声波探伤