He arrived _______ London _______ a cold winter night. [ ]

A. at; at

B. in; on

C. in; in

D. \; on

旧钢管表面锈蚀深度应不大于（）mm。锈蚀检查应每年一次。

A.0.18

B.0.2

C.0.24

D.0.1