错误:
Na2S %2B CrCl3 %2B H2O %3D Cr%28OH%293 %2B H2S %2B NaCl
^不需要的字符 ('%')Na2S %2B CrCl3 %2B H2O %3D Cr%28OH%293 %2B H2S %2B NaCl
^不需要的字符 ('%')