\begin{table}%t1
\caption{\label{tab1}The mass and the envelope mass of normal hot subdwarf
stars.}
%%\centerline

{\small
\begin{tabular}{lcc}
\hline \hline
 Type  &  $M_{\rm f}$  &  $M_{\rm env}$ \\ 
 & ($M_{\odot}$) & ($M_{\odot}$) \\ 
\hline
   conservative case:  \\
sdB   &  0.33--0.67  &  0.01--0.05 \\  % &   2.24--3.55 \\
sdOB  &  0.61--0.86  &  0.05--0.10 \\  %&   3.98--4.47 \\
sdO   &  0.75--1.44  &  0.07--0.22 \\  %&   5.01--6.31 \\
\hline
   nonconservative case:  \\
sdB   &  0.32--0.61  &  0.01--0.05 \\  %&   2.24--3.55 \\
sdOB  &  0.60--0.85  &  0.05--0.09 \\ % &   3.98--4.47 \\
sdO   &  0.81--1.36  &  0.08--0.19  \\
\hline
\end{tabular}}
\par
\medskip
$M_{\rm f} =$ the mass of hot subdwarfs; $M_{\rm env} =$ the envelope mass of hot subdwarfs.
\end{table}