diff --git a/src/utils/ckip.py b/src/utils/ckip.py
index f136d50..23d192e 100644
--- a/src/utils/ckip.py
+++ b/src/utils/ckip.py
@@ -8,9 +8,9 @@ def clean(sentence_ws, sentence_pos):
     short_sentence = []
     stop_pos = set(['Nep', 'Nh', 'Nb'])
     for word_ws, word_pos in zip(sentence_ws, sentence_pos):
-        is_N_or_V = word_pos.startswith('V') or word_pos.startswith('N')
+        is_n_or_v = word_pos.startswith('V') or word_pos.startswith('N')
         is_not_stop_pos = word_pos not in stop_pos
         is_not_one_charactor = not (len(word_ws) == 1)
-        if is_N_or_V and is_not_stop_pos and is_not_one_charactor:
+        if is_n_or_v and is_not_stop_pos and is_not_one_charactor:
             short_sentence.append(f'{word_ws}')
     return ' '.join(short_sentence)