And you're working away until late at night, and you're very, very careful, and you're drinking coffee and you're paying attention, but, occasionally, when you're copying this by hand, you're going to make a little typo, a spelling mistake -- substitute an I for an E, or a C for a T.
直到深夜， 你非常非常小心，喝咖啡保持清醒， 你注意力高度集中，但是时不时地， 当你手抄的时候， 还是会出错 — 抄错字母。 本来是 I 写成了 E，本来是 C 写成了 T。