常把大于等于（）个以上的支路的连接点称为接点。
A、1
B、2
C、3
D、4
参考答案：C
角色行为冲突
If you know that the vessel you are about to call on the VHF radio maintains a radio watch on both the working and the calling frequencies，which frequency should you call on? （）
A.Calling frequency
B.Distress frequency
C.Urgency frequency
D.Working frequency
