title: how to get parse tree using python nltk?
body: <p>Given the following sentence:</p>
  
  <pre><code>The old oak tree from India fell down.
  </code></pre>
  
  <p>How can I get the following parse tree representation of the sentence using python NLTK?</p>
  
  <pre><code>(ROOT (S (NP (NP (DT The) (JJ old) (NN oak) (NN tree)) (PP (IN from) (NP (NNP India)))) (VP (VBD fell) (PRT (RP down)))))
  </code></pre>
  
  <p>I need a complete example which I couldn't find in web!</p>
  
  <hr>
  
  <p><strong>Edit</strong></p>
  
  <p>I have gone through <a href="http://www.nltk.org/book/ch08.html" rel="noreferrer">this book chapter</a> to learn about parsing using NLTK but the problem is, I need a grammar to parse sentences or phrases which I do not have. I have found <a href="https://stackoverflow.com/questions/6115677/english-grammar-for-parsing-in-nltk">this stackoverflow post</a> which also asked about grammar for parsing but there is no convincing answer there.</p>
  
  <p>So, I am looking for a complete answer that can give me the parse tree given a sentence.</p>