title: Find out negative adverbs using NLTK
body: <p>Since adjectives and verbs are able to convey negative sentiments using negative prefixes, I need to find out such phrases from millions of sentences that I have. For example " I am not good at this." is a negative sentence even if "good" is a positive word.</p>
  
  <p>I am using nltk to tag all the sentences. But how would I be able to filter out negative prefixes? Most of negative prefixes like no, not are tagged as adverbs "RB". Does that mean I can use all tagged adverbs as negative prefix? And also the data that I have is huge which makes it difficult for me to come up with a list of negative prefixes.</p>