错误:
MnO4%3A- %2B Br%3A- %2B H%3A%2B %3D Mn%3A2%2B %2B Br2 %2B H2O
^
不需要的字符 ('%')MnO4%3A- %2B Br%3A- %2B H%3A%2B %3D Mn%3A2%2B %2B Br2 %2B H2O
^
不需要的字符 ('%')