Borrowed tongue characters are one of the phenomena of using words in ancient books in China. "Tongue borrowing" means "tongzhuan", that is, words with the same or similar pronunciation are used instead of words. For various reasons, the author did not use this word, but temporarily borrowed words with the same sound or similar sounds to replace it. Some people think that some loanwords are white words (other words) written by the ancients. As a matter of fact, the first person to write a generic character can be said to have written a white character, but later generations have followed suit, and it is a long story. There are a lot of loanwords in ancient books, which is one of the main reasons why ancient books in China are difficult to read.