title: Python_Checking String In a scale of Word
body: <pre><code>def Interpretation_is(sentence):
       #parameter is a sentence#
       if  'there' in sentence:
            print(sentence.replace('is','exists'))
       if 'he' in sentence:
            print(sentence.replace('is','equal to'))
  
  Interpretation_is('there is a woman')
  Interpretation_is('he is a boy')
  </code></pre>
  
  <p>I am trying to make up rephraser of a simple sentence.</p>
  
  <p>Seeing above my code, it prints two reuslts for the first input('there is a woman') because in the word 'there' there already exists 'he' as a part of it.</p>
  
  <p>First, I would like to let the python read it not string by string but check it as a unitary scale of word.</p>
  
  <p>Second, to make up the rephraser of a sentence which contains a predicate 'is', I would like to let the function only check the first word of a given sentence.
  How could I let the program to just check the first word of a sentence? </p>
  
  <p>Any recommendation or reference that I can refer to? </p>