I uses tabularx enviroment and its X coloumn format and solved this problem.

\documentclass{article}

\usepackage{bigstrut}
\usepackage{tabularx}

\begin{document}


\begin{tabularx}{70mm}{|p{20mm}|p{20mm}|l|}
% Table generated by Excel2LaTeX from sheet 'Sheet1'
\hline
A     &amp; B     &amp; C \bigstrut\\
\hline
\multicolumn{3}{|X|}{This is combined from A+B+C, and the contents is very very long.} \bigstrut\\
\hline

\end{tabularx}%

\end{document}


How to specify the multicolumn width in table header?
Can we completely reverse-engineer the source code from java bytecode ? Why this feature is allowed in Java and How successful are java decompilers against obfuscators.?
