我有一个非缩进的段落，我想在它周围放一个方框。你知道怎么做吗？
\documentclass[openany]{book}
\usepackage{amsbsy}
\usepackage{changepage}
\usepackage{geometry}
\geometry{paperheight=9.8125in,paperwidth=8in, left=.5in,
right=.5in,top=.75in,bottom=.4375in }
\usepackage{fancyhdr}
\fancypagestyle{plain}{\fancyhf{} \fancyhead[EL,OR]{\textbf
{\thepage}}\renewcommand{\headrulewidth}{0pt}}
\pagestyle{plain}
\renewcommand{\rmdefault}{pag}
\usepackage[utf8]{inputenc}
\usepackage[hyphens]{url}
\usepackage[authoryear,round]{natbib}
\newcommand{\titlefontarash}{%
\usefont{OT1}{pag}{b}{n}\fontsize{25}{30} \selectfont
}
\newcommand{\basefontarash}{\usefont{OT1}{pag}{b}{n}\fontsize{18}
{\baselineskip} \selectfont}
\newcommand{\datefontarash}{\usefont{OT1}{pag}{m}{n}\fontsize{12}
{\baselineskip} \selectfont}
\begin{document}
\title{\titlefontarash respect respect respect respect respect respect
respect respect respect respect respect respect respect respect respect
respect respect respect respect respect respect respect respect }
\author{\basefontarash good boy}
\date{\datefontarash April 21, 2019}
{
\maketitle
\let\cleardoublepage\relax
\frontmatter
}
\vspace*{\fill}
\begin{center}
\basefontarash To beauty...
\linebreak
\linebreak
\basefontarash To nice...
\end{center}
\vspace*{\fill}
\tableofcontents
\begin{adjustwidth}{2.25in}{0pt}
\mainmatter
Introduction
\chapter{beauty}
fish (\citet{fox(1994)}) number $\pi +15 \pi + \sqrt{145} \Omega +v\pi +
a^2 +2ab + b^2 + \pi +v\pi +\pi +\pi
+\pi +\pi +v\pi +v\pi +\pi +\pi +\pi +\pi +\pi +\pi +\pi +\pi +$ fish
\textbf{RIVER ${\boldsymbol{\pi+\pi+\pi+\pi+\pi+\pi+\pi+\pi+\pi}}$}
(\citet{chicken(1807)})
following .
\noindent \textbf{I WANT TO PUT THE BOX AROUND HERE}\hspace{.1875in} THE
BOX INCLUDES THIS TOO.
THE BOX INCLUDES THIS TOO. THE BOX INCLUDES THIS TOO.THE BOX INCLUDES THIS
TOO.THE BOX INCLUDES THIS TOO.
THE BOX INCLUDES THIS TOO.THE BOX INCLUDES THIS TOO.THE BOX INCLUDES THIS
TOO.
\section{fox1}
\subsection{fox2}
\subsection{fox3}
\subsection{fox4}
\subsection{fox5}
\subsection{fox6}
\subsection{fox7}
Now we are fox...
Let us see what happens
\section{fish}
fish fox dog catfish fox dog catfish fox dog catfish fox dog catfish fox dog
catvfish fox dog catvfish fox dog catfish fox dog catfish fox dog catfish
fox dog catfish fox dog catfish fox dog catfish fox dog catfish fox dog
catfish fox dog catfish fox dog catfish fox dog catfish fox dog catfish fox
dog catfish fox dog catfish fox dog catfish fox dog catfish fox dog catfish
fox dog catfish fox dog catfish fox dog catfish fox dog catfish fox dog
catfish fox dog cat
\section{fish5}
fish fox dog catfish fox dog catfish fox dog catfish fox dog catfish fox dog
catvvfish fox dog catfish fox dog catfish fox dog catfish fox dog catfish
fox dog cat
\section{dog}
fish fox dog catvvvfish fox dog catfish fox dog catfish fox dog catfish fox
dog catfish fox dog cat
\subsection{dog ${\boldsymbol{\pi}}$}
\section{mouse}
\section{milk}
\chapter{pishi}
\end{adjustwidth}
\begin{thebibliography}{9}
\bibitem[fox(1994)]{fox(1994)}fox, T. L. (1994) \textit{fox.} New York: fox.
\bibitem[chicken(1807)]{chicken(1807)}chicken, Z. L. (1807) \textit{fox.}
Boston: cat fish.
\end{thebibliography}
\end{document}
答案1
欢迎来到 TeX.SX！对于这种事情，我最喜欢的工具是彩色盒子包。具体来说，你可以使用：
\begin{tcolorbox}
\noindent \textbf{I WANT TO PUT THE BOX AROUND
HERE}\hspace{.1875in} THE BOX INCLUDES THIS TOO. THE BOX
INCLUDES THIS TOO. THE BOX INCLUDES THIS TOO.THE BOX INCLUDES
THIS TOO.THE BOX INCLUDES THIS TOO. THE BOX INCLUDES THIS
TOO.THE BOX INCLUDES THIS TOO.THE BOX INCLUDES THIS TOO.
\end{tcolorbox}
生产：
顺便说一句，提问时最好能将代码简化为 最小工作示例。这应该是演示问题所需的最少代码，以便它也能编译。在这种情况下，产生上述屏幕截图的 MWE 是：
\documentclass[openany]{book}
\usepackage{tcolorbox}
\begin{document}
fish number $\pi +15 \pi + \sqrt{145} \Omega +v\pi +
a^2 +2ab + b^2 + \pi +v\pi +\pi +\pi
+\pi +\pi +v\pi +v\pi +\pi +\pi +\pi +\pi +\pi +\pi +\pi +\pi +$ fish
\textbf{RIVER ${\pi+\pi+\pi+\pi+\pi+\pi+\pi+\pi+\pi}$}
following .
\begin{tcolorbox}
\noindent \textbf{I WANT TO PUT THE BOX AROUND
HERE}\hspace{.1875in} THE BOX INCLUDES THIS TOO. THE BOX
INCLUDES THIS TOO. THE BOX INCLUDES THIS TOO.THE BOX INCLUDES
THIS TOO.THE BOX INCLUDES THIS TOO. THE BOX INCLUDES THIS
TOO.THE BOX INCLUDES THIS TOO.THE BOX INCLUDES THIS TOO.
\end{tcolorbox}
\section{fox1}
\end{document}
有很多选项可以控制颜色、标题等等。请参阅彩色盒子 手册了解更多详细信息。
正如评论中提到的，另一种选择是使用框架包。在本例中，MWE
\documentclass[openany]{book}
\usepackage{mdframed}
\begin{document}
fish number $\pi +15 \pi + \sqrt{145} \Omega +v\pi +
a^2 +2ab + b^2 + \pi +v\pi +\pi +\pi
+\pi +\pi +v\pi +v\pi +\pi +\pi +\pi +\pi +\pi +\pi +\pi +\pi +$ fish
\textbf{RIVER ${\pi+\pi+\pi+\pi+\pi+\pi+\pi+\pi+\pi}$}
following .
\begin{mdframed}
\noindent \textbf{I WANT TO PUT THE BOX AROUND HERE}\hspace{.1875in} THE
BOX INCLUDES THIS TOO.
THE BOX INCLUDES THIS TOO. THE BOX INCLUDES THIS TOO.THE BOX INCLUDES THIS
TOO.THE BOX INCLUDES THIS TOO.
THE BOX INCLUDES THIS TOO.THE BOX INCLUDES THIS TOO.THE BOX INCLUDES THIS
TOO.
\end{mdframed}
\section{fox1}
\end{document}
生产
与以前一样，有很多选择；请参阅mdframed 手册。