\begin{table}%T1
\caption{\label{tab1}The mean values of parameters for the samples.}
%\centering
$$
\begin{tabular}{rlr@{$~\pm~$}lr@{$~\pm~$}lr@{$~\pm~$}l}%ccc}
\hline
\hline
No.& Parameters& \multicolumn{2}{c}{AGNs} & 
\multicolumn{2}{c}{Stars}   & \multicolumn{2}{c}{Normal galaxies}\\
\hline
1 &$B-R$  & 0.41 & 0.78  &$-$1.53 & 4.19 & 1.42 & 1.49\\
2 &$B+2.5\log~({\it CR})$ &13.66 & 1.83 & 4.18 & 5.33 & 7.95 & 2.40\\
3 &{\it CR} &0.20& 0.43&0.12& 0.42 &0.08& 0.13\\
4 &{\it HR}1&0.09& 0.53&0.09& 0.53 &0.65& 0.37\\
5 &{\it HR}2&0.14& 0.41&$-$0.02& 0.54&0.22& 0.48\\
6 &{\it ext}&6.28& 9.52&4.21& 9.72 &16.11&  32.12\\
7 &{\it extl}&1.88& 6.62&1.05& 6.74 &7.81& 31.15\\
8 &$J-H$&0.73& 0.23&0.24& 1.77&0.76& 0.17\\
9 &$H-K_{\rm s}$&0.76& 0.27&0.09& 0.11&0.37&0.19\\
10 &$J+2.5\log~({\it CR})$&12.80& 1.27&4.33& 1.8&9.75& 1.54\\
\hline
\end{tabular}
$$
\end{table}