\noindent
\begin{center}
\begin{tabular}{|l|c|l|}
\hline
\multicolumn{3}{|c|}{{\vrule height12pt width0pt depth3.5pt\Large
Troff Macros Supported}}\\ 
\hline\hline
macro&	 supported&\multicolumn{1}{|c|}{description}\\
\hline
.ad&	&		line-adjust\\
.af&	&		assign-format\\
.am&	&		append-to-macro\\
.as&	&		append-to-string\\
.bp&	x&		new-page\\
.br&	x&		break\\
.ce&	&		center-input-lines\\
.de&	&		define-macro\\
.ds&	&		define-string\\
.el&	&		conditional-else\\
.ex&	&		terminate processing\\
.fi&	x&		fill-mode\\
.fp&	&		mount-font\\
.ft&	x&		font-switch\\
.hc&	&		hyphen-indicator\\
.hy&	&		hyphenation-on\\
.ie&	&		conditional with else\\
.if&	&		conditional without else\\
.in&	&		line-indent\\
.lc&	&		leader\\
.ll&	&		line-length\\
.ls&	&		line-spacing\\
.lt&	&		title-length\\
.mk&	&		mark-vertical-position\\
.na&	&		no-line-adjust\\
.ne&	&		need-vertical-space\\
.nf&	x&		no-fill\\
.nh&	&		hyphenation-off\\
.nr&	&		define-and-set-number-reg\\
.ns&	&		no-space-mode\\
.nx&	&		change-input-file\\
\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