\documentclass{jsarticle}[12pt]
\begin{document}
\Huge
\begin{tabular}[htbp]{l l l l}
KEY  &      TEXTFONT             &   MATHFONT                \\\hline
C-a  &                           &  $\mathcal{mathcal}      $ \\
C-b  &      \textbf{textbf}      &  $\mathbf{mathbf}        $\\
C-c  &      \textsc{textsc}      &                           \\
C-e  &        \emph{emph}        &                           \\
C-f  &      \textsf{textsf}      &  $\mathsf{mathsf}        $\\
TAB  &      \textit{textit}      &  $\mathit{mathit}         $\\
RET  &      \textmd{textmd}      &                           \\
C-n  &  \textnormal{textnormal}  &  $\mathnormal{mathnormal} $\\
C-r  &      \textrm{textrm}      &  $\mathrm{mathrm}         $\\
C-s  &      \textsl{ textsl}     &                           \\
C-t  &      \texttt{texttt}      &  $\mathtt{mathtt}         $\\
C-u  &      \textup{textup}      &                           \\
C-d  & -- delete font             &                           \\
\hline
\end{tabular}
\end{document}