title: Creating word pairs from phrases
body: <p>Is there any way to get the possible word pairs from word phrases? I have a list of word phrases and I need to find all the possible word pair combinations from it. I can normally tokenize the phrases to get the words and then find all the possible pairs. But if I want to have some pair which consists of one phrase and one word of another phrase then is it possible to do it?
  For example:
  The list of phrases can be something as</p>
  <pre><code>['influenza virus', 'elderberry liquid extract', 'previous study', 'elderberry fruit', 'berry good']
  </code></pre>
  <p>The possible pairs should also contain these</p>
  <pre><code>[(influenza virus,elderberry),(influenza virus, liquid),(influenza virus, extract).....]
  </code></pre>
  <p>Is there any way to do this? I have done the word pairings for individual words. I am looking for something that can do the above.</p>