素 On the HSK 7-9 vocabulary list, at CEFR level C2. sù ㄙㄨˋ raw silk white plain, unadorned vegetarian (food) essence nature element constituent usually always ever 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