我正在尝试将 PdfLatex 编译为 Pdf，但一直出现此错误。我该怎么办？
Undefined control sequence.
l.5 \section
下面是我的代码的一部分
% file name : switch-models.tex
% input to HW-2-main.tex
%
% for compsci190-2013F
\section {FHN switch models}
\begin{itemize}
\item Review of the three switch models in lecture notes
\item Suggestion : think of {\em infinitesimal changes} in time
and the corresponding potential.
\end{itemize}
\vspace{1 cm}
\subsection{Model (1)}
Consider the basic model for a single switch.
答案1
你有多个文件，但主文件必须以开头，\documentclass{style}例如\documentclass{article}，下面显示一个 MWE
\documentclass{article} % %
\begin{document} % %
\section {FHN switch models}
\begin{itemize}
\item Review of the three switch models in lecture notes
\item Suggestion : think of {\em infinitesimal changes} in time
and the corresponding potential.
\end{itemize}
\vspace{1 cm}
\subsection{Model (1)}
Consider the basic model for a single switch.
\end{document} % %