title: Having trouble importing nltk into Python3
body: <p>When I run the command:</p>
  
  <pre><code>pip3 install nltk
  </code></pre>
  
  <p>My terminal outputs:</p>
  
  <pre><code>Requirement already satisfied: nltk in ./Library/Python/2.7/lib/python/site-packages (3.4.5)
  </code></pre>
  
  <p>But when I load up python3, I get:</p>
  
  <pre><code>ModuleNotFoundError: No module named 'nltk'
  </code></pre>
  
  <p>This is driving me crazy, and I'm sure I'm missing something very basic, I just don't understand what!</p>