森林：是什么原因造成了错位？

Question

\RequirePackage{luatex85}
\documentclass[border=1cm]{standalone}
\usepackage{fontspec}
\usepackage[american]{babel}
\usepackage{libertine}
\usepackage[edges]{forest}

\begin{document}
\begin{forest}
forked edges,
[S[subject [pronoun [I]]] [predicate [verb [saw]]] [object [noun [Jane.]]]]
\end{forest}    
\end{document}

Answer 1

像这样？

对于树中节点的对齐，如您所愿，您应该将其告诉forest。请参见下面的 mwe：

\documentclass[border=1cm]{standalone}
\usepackage{fontspec}
\usepackage[american]{babel}
\usepackage{libertine}
\usepackage[edges]{forest}

\begin{document}
\begin{forest}
forked edges,
[S
    [subject
        [pronoun [I]]
    ]
    [predicate,before computing xy={s/.average={s}{siblings}}% <---
        [verb [saw]]
    ] [object
        [noun
            [Jane.]
        ]
    ]
]
\end{forest}
\end{document}