子图

\begin{figure}[h] 

    \centering

    \begin{tabular}{@{}cc@{}}

    \includegraphics[width=.23\textwidth]{figure9a.pdf} &

    \includegraphics[width=.23\textwidth]{figure9b.pdf} \\

      \end{tabular}

    \caption{This is  some figure side by side}

\end{figure}

https://tex.stackexchange.com/questions/84889/combining-multiple-eps-files-into-a-single-figure

\usepackage{subfigure}

%\begin{figure}[h]

%\centering

% when using pdflatex, use pdf file:

%\subfigure{

%\label{fig:subfig:a} %% label for first subfigure

% \includegraphics[width=3.0in]{figure9a.pdf}}

%\hspace{0.05in}

%\subfigure{

%\label{fig:subfig:b} %% label for second subfigure

% \includegraphics[width=1.0in]{figure9b.pdf}}

%\caption{Scatter of CCN number concentration ($S=0.2\%, cm^{-3}$) and ground precipitations ($unit: mm h^{-1}$) with four cases, connected by smoothed lines with different scale ($<30, 30-250, >250$) in 14 sites of Nanjing}

%\label{fig:subfig} %% label for entire figure

%\includegraphics[width=10cm,height=6cm]{picture.pdf}

%\caption{Scatter of CCN number concentration ($S=0.2\%, cm^{-3}$) and ground precipitations ($unit: mm h^{-1}$) with four cases, connected by smoothed lines with different scale ($<30, 30-250, >250$) in 14 sites of Nanjing}\centering

%\label{figone}

%\end{figure}

这两个插入后都不对，后面一个是图片太大了，导致了错乱

https://tex.stackexchange.com/questions/37581/latex-figures-side-by-side

\usepackage{subfig}

\begin{figure}[h]

\centering

\subfloat{\includegraphics[width=5cm]{figure11a.pdf} }%

%\qquad

\subfloat{\includegraphics[width=5cm]{figure11b.pdf}}\\

\subfloat{\includegraphics[width=5cm]{figure11c.pdf} }%

%\qquad

\subfloat{\includegraphics[width=5cm]{figure11d.pdf} }%

\caption{2 Figures side by side}%

\label{figone}%

\end{figure}