\documentclass[11pt]{article}
\usepackage{mathtools}
\usepackage{amssymb}
\usepackage{array}
\begin{document}

\begin{tabular}{|m{2cm}|m{2cm}|m{2cm}|m{2cm}|}\hline
Mon&Tue&Wed&Thu&Fri\\\hline\hline
Classical dynamics&Ocean Earth Science&Classical dynamics&Ocean Earth Science&Basic Physics Experiment\\\hline
Mathmatical Physics&Computational Physics&Mathmatical Physics&Computational Physics&Educational Psychology\\\hline
-&Electrodynamics&-&Electrodynamics&-\\\hline
\end{tabular}

\end{document}

(표 마지막 줄에 - 표시가 군데군데 있습니다)

위와같이 입력했는데 계속 오류가 뜹니다.

뜨는 오류 내용은 다음과 같습니다.

Extra alignment tab has been changed to \cr.
 \endtemplate
                             
l.10 Mon&Tue&Wed&Thu&
                     Fri\\\hline\hline