A is a person going from one place to another in a public or private
vehicle (交通工具).
A:passenger
B:musician
C:winner
如图所示,为永磁体A和电磁铁B之间的磁场分布。请根据图中磁感线的方向标出永磁体A右端的磁极和电磁铁B中电源的“+”、“一”极。