\definecolor{ublue}{rgb}{0.152,0.250,0.545}
\begin{tikzpicture}
\begin{axis}[  
  width=12cm, height=4.5cm, 
  symbolic x coords={未抽取词,do,want,what,am,people,look},
  xtick=data,
  ytick={0,0.05,0.1,0.15,0.2,0.25},
  xlabel={低概率词汇},
  ylabel={词汇概率},
  legend pos=outer north east,
  xlabel style={align=right,xshift=6.5cm,yshift=0.8cm,font=\footnotesize},
  ylabel style={rotate=-90,yshift=2cm,xshift=1cm,font=\footnotesize},
  y tick style={opacity=0},
  x tick style={opacity=0},
  x tick label style={anchor=base,font=\footnotesize,yshift=-0.5cm},
  y tick label style={font=\footnotesize,/pgf/number format/.cd,fixed,precision=2},
  y axis line style={opacity=0},
  tick align=inside,
  ymajorgrids,
  axis x line*=bottom,
  major grid style={dotted,draw=ublue},
  axis on top,
  legend style={anchor=north west,font=\footnotesize},
  ymin=0,
  ymax=0.25]
  \addplot [ybar,bar shift=-2mm,bar width=4mm,fill=blue!40,draw=blue!40,area legend] coordinates{(未抽取词,0) (do,0.05) (want,0.05) (what,0.05) (am,0.1) (people,0.15) (look,0.2)};
  \addplot [ybar,bar shift=2.15mm,bar width=4mm,fill=red!40,draw=red!40,area legend] coordinates{(未抽取词,0.03) (do,0.062) (want,0.062) (what,0.062) (am,0.09) (people,0.122) (look,0.138)};
  \legend{未平滑,平滑后}
\end{axis}
\end{tikzpicture}

%---------------------------------------------------------------------