還原 Simplified: 还原 On the HSK 7-9 vocabulary list, at CEFR level C2. huányuán ㄏㄨㄢˊ ㄩㄢˊ to restore to the original state to reconstruct (an event) reduction (chemistry) Sources CC-CEDICT, CC BY-SA 4.0 pinyinjs, Apache-2.0 国际中文教育中文水平等级标准, 中华人民共和国教育部, MIT