答案1
欢迎来到 TeX.SE!
\documentclass{article}
\begin{document}
\begin{tabular}{|p{1mm}*{4}{|p{5mm}}|}
\hline
& A & B & A & B \\
\hline
\end{tabular}
\end{document}
或者
\documentclass{article}
\begin{document}
\begin{tabular}{|p{1mm}*{4}{|@{\,}p{6mm}}|}
\hline
& A & B & A & B \\
\hline
\end{tabular}
\end{document}