在句法树中画一个圆圈（tikzpicture）

Question

我怎样才能绘制一个包含 phi 和 T 的圆？

\begin{tikzpicture}[scale=0.6]
\tikzset{sibling distance=5em}
\node (top) {}
child[blue] {node {$\phi$}}
child [blue] {node  {}
child [blue]{node {T}}
child {node {}
child[red] {node {Mood}}
child [red]{node {}
child {node {Asp}}
child {node {}
child {node {Cause}}
child {node {Proc}}
}}}};
\end{tikzpicture}

Answer 1

像这样？

\documentclass[a4paper,12pt]{beamer}
\usepackage{tikz-qtree}
\begin{document}
\begin{tikzpicture}[scale=0.6]
\tikzset{sibling distance=5em}
\draw[blue] (-.5,-2.2) circle (40pt);
\node (top) {}
child[blue] {node {$\phi$}} 
child [blue] {node  {}
child [blue]{node {T}}
child {node {}
child[red] {node {Mood}}
child [red]{node {}
child {node {Asp}}
child {node {}
child {node {Cause}}
child {node {Proc}}
}}}};
\end{tikzpicture}
\end{document}

或用虚线圆圈。

\documentclass[a4paper,12pt]{beamer}
\usepackage{tikz-qtree}
\begin{document}
\begin{tikzpicture}[scale=0.6]
\tikzset{sibling distance=5em}
\draw[blue, dotted] (-.5,-2.2) circle (40pt);
\node (top) {}
child[blue] {node {$\phi$}} 
child [blue] {node  {}
child [blue]{node {T}}
child {node {}
child[red] {node {Mood}}
child [red]{node {}
child {node {Asp}}
child {node {}
child {node {Cause}}
child {node {Proc}}
}}}};
\end{tikzpicture}
\end{document}