子图垂直竖版-latex

\begin{figure}[!t]
\centering
\begin{subfigure}{0.49\textwidth}
\centering
\includegraphics[width=300pt,height=200pt,angle=90]{figure1.pdf}
\caption{caption1}
\end{subfigure}
\begin{subfigure}{0.49\textwidth}
\centering
\includegraphics[width=300pt,height=200pt,angle=90]{figure2.pdf}
\caption{caption2}
\end{subfigure}
\begin{subfigure}{0.49\textwidth}
\centering
\includegraphics[width=300pt,height=200pt,angle=90]{figures3.pdf}
\caption{caption3}
\end{subfigure}
\begin{subfigure}{0.49\textwidth}
\centering
\includegraphics[width=300pt,height=200pt,angle=90]{figure4.pdf}
\caption{caption4}
\end{subfigure}
\caption{caption}
\label{fig}
\end{figure}