diff --git a/harvesttext/__init__.py b/harvesttext/__init__.py
index 77dccad..467220f 100644
--- a/harvesttext/__init__.py
+++ b/harvesttext/__init__.py
@@ -4,7 +4,7 @@
 from .harvesttext import HarvestText
 from .resources import *
 
-__version__ = '0.8.1.1'
+__version__ = '0.8.1.2'
 
 def saveHT(htModel,filename):
     with open(filename, "wb") as f:
diff --git a/harvesttext/summary.py b/harvesttext/summary.py
index 9cdec46..b5a1885 100644
--- a/harvesttext/summary.py
+++ b/harvesttext/summary.py
@@ -29,8 +29,11 @@ def get_summary(self, sents, topK=5, stopwords=None, with_importance=False, stan
         # 使用standard_name,相似度可以基于实体链接的结果计算而更加准确
         sent_tokens = [self.seg(sent.strip(), standard_name=standard_name, stopwords=stopwords) for sent in sents]
         if self.language == "en":
-            from pattern.en import lemma
-            sent_tokens = [[lemma(wd) for wd in sent] for sent in sent_tokens]
+            try:
+                from pattern.en import lemma
+                sent_tokens = [[lemma(wd) for wd in sent] for sent in sent_tokens]
+            except:
+                print(" `pattern` is not installed, so the english words will not be lemmatized, this might slightly hurt the summary quality")
         sent_tokens = [sent for sent in sent_tokens if len(sent) > 0]
         G = nx.Graph()
         for u, v in combinations(range(len(sent_tokens)), 2):
diff --git a/requirements.txt b/requirements.txt
index 4b19c49..6e5a794 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -13,5 +13,4 @@ python-louvain
 tqdm
 w3lib
 nltk
-opencc-python-reimplemented
-pattern
\ No newline at end of file
+opencc-python-reimplemented
\ No newline at end of file