如何将两幅图放在同一页上？

Question

我有以下图形，需要放在 1 页上，但它为每个图形创建一个单独的页面，我不知道为什么？

\begin{figure}[!htb]\centering
\includegraphics[width=1\textwidth]{HIV-AIDSIII.pdf}
\setlength{\textfloatsep}{10pt plus 1.0pt minus 2.0pt}
\caption{$p=0.3$, $q=0.4$, $r=0.5$, $\xi_1 =0.001$, $\xi_2 =0.003$  hence $\mathcal{R}_0 \approx 3.204$.}
\end{figure}

\begin{figure}[!htb]\centering
\includegraphics[width=1\textwidth]{HIV-AIDSIV.pdf}
\setlength{\textfloatsep}{10pt plus 1.0pt minus 2.0pt}
\caption{Density plotted against time for HIV-AIDS model with $S\left(0\right)=50$, $I_1\left(0\right)=0.50$, $I_2\left(0\right)=50$, $J\left(0\right)=20$ and $A\left(0\right)=20$.}
\end{figure}