①0.2mol/L的H₂O₂溶液，25℃；②0.2mol/L的H₂O₂溶液，MnO₂，25℃；

③0.2mol/L的H₂O₂溶液，35℃；④0.2mol/L的H₂O₂溶液，MnO₂，35℃．

用激光笔沿图中所示的PO方向照射，一定能照射到尚未移动的小鱼或小鸟的是（　　）

  The students were having their chemistry（化学）class. Miss Li was telling the children what water was like. After that, she asked her students, “What's water?" No one spoke for a few minutes．Miss Li asked again，“Why don't you answer my question？Didn't I tell you what water is like？”
Just then a boy put up his hand and said，"Miss Li，you told us that water has no color and no smell．But where to find such kind of water？The water in the river behind my house is always black and it has a bad smell．"Most of the children agreed With him．
“I'm sorry，children．”said the teacher，"Our water is getting dirtier and dirtier．That's a problem”．

下列结构示意图表示阴离子的是（　　）