之所以 On the HSK 7-9 vocabulary list, at CEFR level C2. zhīsuǒyǐ ㄓ ㄙㄨㄛˇ ㄧˇ (after a noun N and before a predicate P) the reason why N P Example: 我之所以討厭他|我之所以讨厌他[wo3 zhi1 suo3 yi3 tao3 yan4 ta1] "the reason why I dislike him (is ...)" 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