Latex中文下划线自动换行

\documentclass[UTF8]{ctexart}

\usepackage{xeCJKfntef}

\begin{document}

\CJKunderline{芜湖起飞芜湖起飞芜湖起飞芜湖起飞芜湖起飞芜湖起飞芜湖起飞芜湖起飞芜湖起飞芜湖起飞芜湖起飞芜湖起飞芜湖起飞芜湖起飞芜湖起飞}

\end{document}

来源：https://tex.stackexchange.com/questions/385742/underline-in-mid-chinese-text

英文看这个：https://blog.csdn.net/qq_41961459/article/details/132892356