—You don't go to school by bus, do you?

—______. But sometimes I walk.         [ ]

A. Yes, I do          

B. No, I don't

C. I by bus          

D. I take the subway

毛坯中锻件的（）要比铸件好。

A.机加工性能

B.硬度

C.力学性能

D.所有性能