%%%------------------------------------------------------------------------------------------------------------
%%%  tree binarization
\begin{center}
\begin{tikzpicture}

{\small
\begin{scope}[scale = 0.9, sibling distance=25pt, level distance=30pt]

{\footnotesize
\Tree[.IP
     	[.NP ]
     	[.VP ]
        [., ]
        [.VP ]
        [., ]
        [.VP ]
        [., ]
        [.VP ]
        [.{.{\color{white} V}} ]
     ]
}
\end{scope}
}

\end{tikzpicture}
\end{center}