\noindent
\begin{center}
\begin{tabular}{|l|c|l|}
\hline
\multicolumn{3}{|c|}{{\vrule height12pt width0pt depth3.5pt\Large
Troff Macros Supported con't}}\\ 
\hline\hline
macro&	 supported&\multicolumn{1}{|c|}{description}\\
\hline
.pl&	&		page-length\\
.pn& 	&		page-number\\
.po&	&		page-offset\\
.ps&	x&		point-size\\
.rd&	&		read\\
.rm&	&		remove-macro-or-string\\
.rr&	&		remove-register\\
.rs&	&		restore-space-mode\\
.rt&	&		return-to-vertical-position\\
.so&	&		include-file\\
.sp&	x&		vertical-space\\
.ss&	&		space-size\\
.sy&	&		execute-UNIX-command\\
.ta&	&		set-tabs\\
.ti&	&		temporary-line-indent\\
.tl&	&		title\\
.tm&	&		write\\
.tr&	&		translate-characters\\
.vs&	&		vertical-space\\
\hline
\hline
x&\multicolumn{2}{|l|}{implemented}\\
p&\multicolumn{2}{|l|}{partially implemented; not all options available}\\
?&\multicolumn{2}{|l|}{implemented but effect is not fully standard}\\
\hline
\end{tabular}\end{center}
\medskip