—How did you come here? I didn't see you just now.

—I got here ______ foot. [ ]

A. by

B. in

C. with

D. on

要解决私人劳动与社会劳动的矛盾，必须通过（）。

A.市场法规

B.宏观调控

C.商品交换

D.商品消费