热油管路输送过程中，油流的温降可分为沿管道直径方向的径向温降和沿管道介质走向的（）温降。
A.平行
B.轴向
C.逆向
D.同向
参考答案：B
警告是公安机关对违反治安管理行为人以( )作出的谴责和告诫。
A．口头方式
B．书面方式
C．口头或书面方式
D．羁押方式
Alice has gone to the classroom and she didn't say _____. [ ]
A. when did she come back
B. when would she be back
C. when she came back
D. when she would be back
