获取错误缺少 \begin{document}。 \begin{document}

Question

\documentclass[aps,prb,preprint,groupedaddress,showkeys]{revtex4}
\RequirePackage{lineno}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\newtheorem{theorem}{Theorem}[section]
\newtheorem{defin}{Definition}
\newtheorem{corollary}{Corollary}[theorem]
\newtheorem{lemma}[theorem]{Lemma}
\newtheorem{remark}{Remark}
\usepackage{catoptions}
\begin{document}
h

\end{document}