答案1
尝试这个:
\documentclass[10pt,a4paper]{article}
\usepackage{framed,lipsum}
\begin{document}
\lipsum[1]
\begin{leftbar}
\noindent
\lipsum[2]
\end{leftbar}
\lipsum[3]
\end{document}
输出:
第二种解决方案:
\documentclass[10pt,a4paper]{article}
\usepackage{framed,lipsum}
\begin{document}
\lipsum[1]
\begin{tabular}{|lp{10cm}}
\textit{Proof}:& \lipsum[1]\\
& \lipsum[5]
\end{tabular}
\end{document}
输出: