Bain回路属于Mapleson系统中的哪种原理（）
A.A回路
B.B回路
C.C回路
D.D和F回路
E.E回路
参考答案：D
—Excuse me. ________?
—I'm sorry I don't know. You can ask the policeman over there. [ ]
A. Where are you going
B. What can I do for you
C. Are you a stranger here
D. Where's the nearest hotel
B/L上做了下列批注，在法律上有效的有（）.
A.记载了件数，加批了“重量不知”
B.记载货物包装表面浅露，货物有损，加批了“质量不知”
C.A+B
D.A和B都无效
