\begin{table}%T1
%\centering
\par
\caption{The spectroscopic observing log of II Peg.}\label{tab1} 
\begin{tabular}{llll} 
\hline\hline 
JD(Hel.) & Phase & Exp. time (s) & $S/N$\\ 
\hline
1. July-Aug. 1999\\
    2451386.2233  &0.1748&3600&200\\
    2451386.2764  &0.1827&5400&200\\
    2451387.2450  &0.3267&5400&170\\
    2451387.3096  &0.3363&5400&180\\
    2451388.2278  &0.4729&5400&150\\
    2451388.2946  &0.4828&5400&120\\
    2451389.2245  &0.6211&5400&120\\
    2451389.2937  &0.6314&3600&120\\
    2451391.1983  &0.9146&3600&160\\
    2451392.2233  &0.0671&5400&140\\
    2451392.2681  &0.0737&1800&140\\
    2451392.3010  &0.0786&3600&200\\
2. Feb. 2000\\
    2451593.9570  &0.0676&2400&170\\
    2451594.9589  &0.2166&2400&160\\
    2451595.9625  &0.3659&3600&85\\
    2451596.9567  &0.5137&3600&120\\
    2451597.9602  &0.6629&3000&170\\
    2451598.9557  &0.8110&3000&150\\
3. Nov.-Dec. 2001\\
    2452237.0161  &0.6993&1800&160\\
    2452238.0092  &0.8470&5400&160\\
    2452238.9832  &0.9918&3300&190\\
    2452239.9882  &0.1413&4200&160\\
    2452240.9630  &0.2862&2400&160\\
    2452242.9929  &0.5881&4500&190\\
    2452243.9588  &0.7317&2400&200\\
    2452244.9763  &0.8831&4800&190\\
\hline 
\end{tabular} 
\end{table}