的确是some key words的部分有问题
你可以试试我修改过后的程式码
\documentclass[12pt,a4paper]{article}
\begin{document}
\title{paper title}
\author{BY KAO\\
School of Mathematica\\
85287, U.S.A.\\
789@asu.edu\\
AND PHOA\\
Institute of Statis\\
123456@webmail.tw}
\maketitle
\begin{abstract}
Abstract
\end{abstract}
\textit {Some key words} : Key words
\section{Introduction}
Introduction
\end{document}