A.1m,1.5m B.1m,1.2m C.1.2m,1.5m D.1m,1m
A.2m/s B.3m/s C.4m/s D.5m/s
A.窗内1m处 B.窗外1.2m处 C.窗外1m处 D.窗外1.5m处