A:A model.
B:A writer.
C:A teacher.
已知:铁氰化钾溶液与Fe2+反应生成带有特征蓝色的沉淀.
—Do you think I should get a good camera ?—Yes , of course ._______, you also need a good map and comfortable shoes.
在既没有指向标,也没有经纬网的地图上辨别方向通常是( )