title: Regular expression to extract whole sentences with matching word
body: <p>I would like to extract sentences with the word "flung" in the whole text. </p>
  
  <p>For example, in the following text, I'd like to extract the sentence "It was exactly as if a hand had clutched them in the centre and flung them aside." using regular expression.</p>
  
  <p>I tried to use this <code>.*? flung (?&lt;sub&gt;.*?)\.</code>, but it starts searching from the beginning of the line. </p>
  
  <p>How could I solve the problem?</p>
  
  <blockquote>
    <p>As she did so, a most extraordinary thing happened. The bed-clothes gathered themselves together, leapt up suddenly into a sort of peak, and then jumped headlong over the bottom rail. It was exactly as if a hand had clutched them in the centre and flung them aside. Immediately after, .........</p>
  </blockquote>