add some stopwords

Senseval_Prep/senseval_preprocessing.py

@@ -29,6 +29,9 @@ def get_stopword_list(stop_path):
         stopli = []
         for line in f:
             stopli.append(line[:-1])
+        stopli.append("n't")
+        stopli.append("'m")
+        stopli.append("whether")
         return stopli
 
 def get_infos(tree_path):