\definecolor{ublue}{rgb}{0.152,0.250,0.545}
\definecolor{ugreen}{rgb}{0,0.5,0}




%%% outline
%-------------------------------------------------------------------------
\begin{tikzpicture}

\node [anchor=west] (label1) at (0,0) {总词数：$6 + 8 + 5 = 20$};
\node [anchor=north west] (p1) at (label1.south west) {$\textrm{P}(\textrm{“很”})=1/20=0.05$};
\node [anchor=north west] (p2) at (p1.south west) {$\textrm{P}(\textrm{“。”})=3/20=0.15$};
\node [anchor=north west] (p3) at (p2.south west) {$\textrm{P}(\textrm{“确实”})=1/20=0.05$};



\node [anchor=north west] (label11) at ([xshift=18.0em,yshift=1.63em]label1.south west) {更多数据-总词数:100K $\sim$ 1M};
\node [anchor=north west] (p12) at (label11.south west) {$\textrm{P}(\textrm{“很”})=0.000010$};
\node [anchor=north west] (p22) at (p12.south west) {$\textrm{P}(\textrm{“。”})=0.001812$};
\node [anchor=north west] (p32) at (p22.south west) {$\textrm{P}(\textrm{“确实”})=0.000001$};



\begin{pgfonlayer}{background}
{
\node[rectangle,draw=ublue, inner sep=0mm] [fit =(label1)(label11)(p3)(p32)] {};
}
\end{pgfonlayer}

\end{tikzpicture}
%---------------------------------------------------------------------