%%%------------------------------------------------------------------------------------------------------------
%%% 调序模型1：基于距离的调序
\begin{center}
\begin{tikzpicture}

\begin{scope}[minimum height = 20pt]

\node[anchor=east] (s0) at (-0.5em, 0) {$\seq{s}$：};
\node[anchor=west,fill=green!20,draw,thick,rounded corners=0.3em] (s1) at (0, 0) {\footnotesize{在 桌子 上 的}};
\node[anchor=west,fill=red!20,draw,thick,rounded corners=0.3em] (s2) at ([xshift=2em]s1.east) {\footnotesize{苹果}};

\node[anchor=east] (t0) at (-0.5em, -1.5) {$\seq{t}$：};
\node[anchor=west,fill=red!20,draw,thick,rounded corners=0.3em] (t1) at (0, -1.5) {\footnotesize{the apple}};
\node[anchor=west,fill=green!20,draw,thick,rounded corners=0.3em] (t2) at ([xshift=2em]t1.east) {\footnotesize{on the table}};

\path[<->, thick] ([yshift=-0.1em]s1.south) edge ([yshift=0.1em]t2.north);
\path[<->, thick] ([yshift=-0.1em]s2.south) edge ([yshift=0.1em]t1.north);

\end{scope}
\end{tikzpicture}
\end{center}