How to indent the first line in columns?

Question

I tried to indent the first line of text. It worked in the contents outside columns. Is there any ways that can work inside the columns? I find no answers through google. Can anyone help me? My code:

\documentclass{beamer}
\usepackage[UTF8, 10pt]{ctex}
\usepackage{subcaption}

\setlength{\parindent}{2em}
\addtobeamertemplate{frametitle}{\setlength{\parindent}{0em}}{}

\begin{document}

\begin{frame}[t]\frametitle{Motivation}

\begin{columns}[T]

    \begin{column}{.5\textwidth}
        the quick brown fox jumps over the lazy dog,the quick brown fox jumps over the lazy dog,the quick brown fox jumps over the lazy dog,the quick brown fox jumps over the lazy dog,the quick brown fox jumps over the lazy dog,
        \begin{itemize}
            \item a
            \item b
            \item c
        \end{itemize}

        稀疏交互的含义是：

        \textcolor{red}{传统的全连接网络}每层的$m$个input和$n$个output之间都有连接，

        \textcolor{red}{卷积网络}的input和output之间是稀疏连接，
    \end{column}

    \begin{column}{.5\textwidth}
        \vspace{-.9\baselineskip}

        \begin{figure}[t]

            \centering
            \begin{subfigure}{.5\textwidth}
                \centering
                \includegraphics[width=\linewidth]{example-image}
                \caption{view from below}
            \end{subfigure}
            \begin{subfigure}{.5\textwidth}
                \centering
                \includegraphics[width=\linewidth]{example-image}
                \caption{view from above}
            \end{subfigure}
            \caption{Caption here}
            \label{fig:figure1}
        \end{figure}
    \end{column}


\end{columns}

\end{frame}
\end{document}

Result:

Answer 1

You could do it manually, using \hspace*{2em} or \setlength{\parindent}{2em} if it should affect the whole column.

\documentclass{beamer}
%\usepackage[UTF8, 10pt]{ctex}
\usepackage{subcaption}

\setlength{\parindent}{2em}
\addtobeamertemplate{frametitle}{\setlength{\parindent}{0em}}{}


\begin{document}

\begin{frame}[t]\frametitle{Motivation}
text

\begin{columns}[T, onlytextwidth]

    \begin{column}{.45\textwidth}
            \setlength{\parindent}{2em}
        the quick brown fox jumps over the lazy dog,the quick brown fox jumps over the lazy dog,the quick brown fox jumps over the lazy dog,the quick brown fox jumps over the lazy dog,the quick brown fox jumps over the lazy dog,
        \begin{itemize}
            \item a
            \item b
            \item c
        \end{itemize}

        text

        \textcolor{red}{ text}每层的 text，

        \textcolor{red}{ text} text，
    \end{column}

    \begin{column}{.45\textwidth}
        \vspace{-.9\baselineskip}

        \begin{figure}[t]

            \centering
            \begin{subfigure}{.5\textwidth}
                \centering
                \includegraphics[width=\linewidth]{example-image}
                \caption{view from below}
            \end{subfigure}
            \begin{subfigure}{.5\textwidth}
                \centering
                \includegraphics[width=\linewidth]{example-image}
                \caption{view from above}
            \end{subfigure}
            \caption{Caption here}
            \label{fig:figure1}
        \end{figure}
    \end{column}


\end{columns}

\end{frame}
\end{document}