Understanding parse trees

Parse trees represent hierarchical relationships between elements of text. For example, a dependency tree shows the relationship between the grammatical elements of a sentence. Let's reconsider the following sentence:

The cow jumped over the moon.

A parse tree for the sentence is shown here. It was generated using the techniques found in Using the LexicalizedParser class later in this chapter:

(ROOT
  (S
    (NP (DT The) (NN cow))
    (VP (VBD jumped)
      (PP (IN over)
        (NP (DT the) (NN moon))))
    (. .)))

The sentence can be graphically depicted as shown in the following figure. It was generated using the application found at http://nlpviz.bpodgursky.com/home. Another editor that allows you to examine text in a graphical manner is GrammarScope (http://grammarscope.sourceforge.net/). This is a Stanford supported tool that uses a Swing-based GUI to generate a parse tree, a grammatical structure, typed dependencies, and a semantic graph of text.

However, there...