How to let multiple figures in right position

Question

I inserted four figures, one by one. And then I added one paragraph of content. But I find the paragraph between the figures - First two figures, then one paragraph, and then one figure. How can I keep the position of the figures in the right place?

My code is like this:

\documentclass{article}    
\usepackage{subfigure}    
\begin{document}    
\begin{figure}[hbtp]    
\centering    
\includegraphics[scale=1]{C:/Users/tr/Pictures/Experiment1.png}    
\caption{First Time Experiment}    
\end{figure}    
\begin{figure}[hbtp]    
\centering    
\includegraphics[scale=1]{C:/Users/tr/Pictures/Experiment2.png}    
\caption{Second Time Experiment}    
\end{figure}    
\begin{figure}[hbtp]    
\centering    
\includegraphics[scale=1]{C:/Users/tr/Pictures/Experiment3.png}    
\caption{Third Time Experiment}    
\end{figure}    
\begin{figure}[hbtp]    
\centering    
\includegraphics[scale=1]{C:/Users/tr/Pictures/Experiment4.png}    
\caption{Fourth Time Experiment}    
\end{figure}

As the figures do, the researcher observes the following principles: ajie%
As the figures do, the researcher observes the following principles: ajie%
As the figures do, the researcher observes the following principles: ajie%
As the figures do, the researcher observes the following principles: ajie\\%\
\end{document}

Answer 1

It's not clear to me if the four graphs should be stacked vertically, or if two will fit next to each other; the sketch you posted seems to suggest the latter.

If two figures can fit side-by-side, I suggest you use a single figure environment, with four minipage environments sized to contain one graph and one \caption instruction. Note that it's not necessary to load the subfigure package (which, anyway, has long been deprecated and shouldn't be used anymore).

\documentclass{article}    
\usepackage[demo]{graphicx}   % don't use "demo" option in real document   
\begin{document}    

\begin{figure}  
\begin{minipage}{0.45\textwidth} 
\includegraphics[width=\linewidth]{C:/Users/tr/Pictures/Experiment1.png}    
\caption{First Time Experiment}    
\end{minipage}    
\hspace{\fill}  %% no blank line before of after this instruction
\begin{minipage}{0.45\textwidth} 
\includegraphics[width=\linewidth]{C:/Users/tr/Pictures/Experiment2.png}    
\caption{Second Time Experiment}    
\end{minipage}    

\vspace{0.75cm}
\begin{minipage}{0.45\textwidth} 
\includegraphics[width=\linewidth]{C:/Users/tr/Pictures/Experiment3.png}    
\caption{Third Time Experiment}    
\end{minipage}    
\hspace{\fill} %% no blank line before of after this instruction
\begin{minipage}{0.45\textwidth} 
\includegraphics[width=\linewidth]{C:/Users/tr/Pictures/Experiment4.png}    
\caption{Fourth Time Experiment}    
\end{minipage}    

\end{figure}

As the figures do, the researcher observes the following principles: ajie%
As the figures do, the researcher observes the following principles: ajie%
As the figures do, the researcher observes the following principles: ajie%
As the figures do, the researcher observes the following principles: ajie\\%\

\end{document}

If, on the other hand, the four graphs need to be stacked vertically, and if the four graphs and their captions can all fit on a single page, I still suggest you use a single figure environment. Note that LaTeX will almost certainly place such a tall figure on a page by itself.

\documentclass{article}    
\usepackage[demo]{graphicx}    
\begin{document}    

\begin{figure}   
\centering

\includegraphics[scale = 1]{C:/Users/tr/Pictures/Experiment1.png}    
\caption{First Time Experiment}    

\vspace{0.75cm}
\includegraphics[scale = 1]{C:/Users/tr/Pictures/Experiment2.png}    
\caption{Second Time Experiment}    

\vspace{0.75cm}
\includegraphics[scale = 1]{C:/Users/tr/Pictures/Experiment3.png}    
\caption{Third Time Experiment}    

\vspace{0.75cm}
\includegraphics[scale = 1]{C:/Users/tr/Pictures/Experiment4.png}    
\caption{Fourth Time Experiment}    

\end{figure}

\end{document}

Answer 2

Quick fix: Use h! option for 4th (and 5th, 6th, ...) figure environment.