\begin{table}%t7
%\centering
\par
\caption{\label{tab:Tex}Values of $T_{\rm ex}$ [K] derived using the two  
methods.}
\begin{tabular}{cccc}
\hline\hline
$\alpha,\delta$ offsets&\multicolumn{2}{c}{\it method 1}&{\it method 2}\\
$[\arcsec ,\arcsec$] & C$_{2}$H(1$-$0) & C$_{2}$H(2$-$1) & \\
\hline
\multicolumn{4}{c}{L1498}\\
0, 0 & $4.0\pm0.1$ & $4.6\pm0.6$ & $4.2\pm0.6$\\
60, $-$40 & $4.1\pm0.1$ & $4.3\pm0.8$ & $4.4\pm0.5$\\
\hline
\multicolumn{4}{c}{CB246}\\
0,0 & $4.1\pm0.1$ & $4.9\pm1.0$ & $4.4\pm0.9$\\
15, $-$30 & $4.1\pm0.3$ & $4.4\pm0.7$ & $4.4\pm0.4$\\
--60, 15 & $4.0\pm0.2$ & $3.9\pm0.4$ & $3.8\pm0.6$\\
\hline
\end{tabular}
\end{table}