\begin{figure}[t]
  \centering
  \begin{subfigure}{0.234\textwidth}
    \centering
    \includegraphics[width=\linewidth]{figure/Figure_37l.png}
    \caption{Feature correlation of ``Baseline'' on Avazu.}
    \label{fig:subfig1}
  \end{subfigure}
  % \hfill
  \begin{subfigure}{0.234\textwidth}
    \centering
    \includegraphics[width=\linewidth]{figure/Figure_1l.png}
    \caption{Feature correlation of SCE on Avazu.}
    \label{fig:subfig2}
  \end{subfigure}
  \caption{Spurious correlation elimination of RE-SORT.}
  \label{decorrelation}
\end{figure}