错误:
Fe2%28SO4%293 %2B NH4OH %3D Fe%28OH%293 %2B %28NH4%292SO4
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不需要的字符 ('%')Fe2%28SO4%293 %2B NH4OH %3D Fe%28OH%293 %2B %28NH4%292SO4
^
不需要的字符 ('%')