

%%% outline
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\begin{tikzpicture}

\node [draw,red,fill=red!10,thick,anchor=center,circle,inner sep=3.5pt] (s1) at (0,0) {\black{$\seq{s}$}};
\node [draw,ublue,fill=blue!10,thick,anchor=center,circle,inner sep=2pt] (t) at ([xshift=1in]s1.east) {\black{$\widehat{\seq{t}}$}};

\draw [->,thick,] (s1.north east) .. controls +(north east:1em) and +(north west:1em).. (t.north west) node[pos=0.5,below] {\tiny{正确翻译}};


\node [draw,red,fill=red!10,thick,anchor=center,circle,inner sep=3.5pt] (s) at ([xshift=13em,yshift=0em]s1.east) {\black{$\seq{s}$}};
\node [draw,ublue,fill=blue!10,thick,anchor=center,circle,inner sep=2pt] (t1) at ([xshift=1in]s.east) {\black{$\seq{t}_1$}};
\node [draw,ublue,fill=blue!10,thick,anchor=center,circle,inner sep=2pt] (t2) at ([xshift=3em,yshift=2em]t1.north east) {\black{$\seq{t}_2$}};
\node [draw,ublue,fill=blue!10,thick,anchor=center,circle,inner sep=2pt] (t3) at ([xshift=1em,yshift=4em]t1.north east) {\black{$\seq{t}_3$}};
\node [draw,ublue,fill=blue!10,thick,anchor=center,circle,inner sep=2pt] (t4) at ([xshift=3em,yshift=-1.5em]t1.north east) {\black{$\seq{t}_4$}};

\node [draw,dashed,ublue,fill=blue!10,thick,anchor=center,circle,minimum size=18pt] (t5) at ([xshift=3em]t3.east) {};
\node [draw,dashed,ublue,fill=blue!10,thick,anchor=center,circle,minimum size=18pt] (t6) at ([xshift=3em]t2.east) {};
\node [draw,dashed,ublue,fill=blue!10,thick,anchor=center,circle,minimum size=18pt] (t7) at ([xshift=3em]t4.east) {};

\draw [->,thick] (s.north east) .. controls +(north east:1em) and +(north west:1em).. (t1.north west) node[pos=0.5,below] {\tiny{$\funp{P} (\seq{t}_1|\seq{s})=0.1$}};
\draw [->,thick] (s.60) .. controls +(50:4em) and +(west:1em).. (t2.west) node[pos=0.5,below] {\tiny{$\funp{P}(\seq{t}_2|\seq{s})=0.2$}};
\draw [->,thick] (s.north) .. controls +(70:4em) and +(west:1em).. (t3.west) node[pos=0.5,above,xshift=-1em] {\tiny{$\funp{P}(\seq{t}_3|\seq{s})=0.3$}};
\draw [->,thick] (s.south east) .. controls +(300:3em) and +(south west:1em).. (t4.south west) node[pos=0.5,below] {\tiny{$\funp{P}(\seq{t}_4|\seq{s})=0.1$}};

\node [anchor=center] (foot1) at ([xshift=3.8em,yshift=-3.5em]s1.south) {\small{（a） 人的翻译候选空间}};
\node [anchor=center] (foot2) at ([xshift=7em,yshift=-3.5em]s.south) {\small{（b） 机器的翻译候选空间}};


\end{tikzpicture}



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