Dimethylation
二甲基化作用, 二甲基取代作用
??? 情景例句
What university did you graduate from?
你從哪所大學畢業的？
Why tell you?
沒必要對你說。
Many firms, for instance, have great difficulty in obtaining technical or scientific books from libraries
比如，很多公司向圖書館借閱科技書籍時感到很困難，