fix English part of README

README.md

@@ -400,6 +400,7 @@ Main Functions
 
 **Code example: segmentation**
 
+```python
 #encoding=utf-8
 import jieba
 
@@ -414,6 +415,7 @@ Main Functions
 
 seg_list = jieba.cut_for_search("小明硕士毕业于中国科学院计算所，后在日本京都大学深造")  # 搜索引擎模式
 print ", ".join(seg_list)
+```
 
 Output:
 
@@ -474,6 +476,7 @@ Use: `jieba.analyse.textrank(raw_text)`.
 * Tags the POS of each word after segmentation, using labels compatible with ictclas.
 * Example:
 
+```pycon
 >>> import jieba.posseg as pseg
 >>> words = pseg.cut("我爱北京天安门")
 >>> for w in words:
@@ -483,6 +486,7 @@ Use: `jieba.analyse.textrank(raw_text)`.
 爱 v
 北京 ns
 天安门 ns
+```
 
 5) : Parallel Processing
 -----------