class Sentence(object):
	
	WORD_TOKENIZER = MyPottsTokenizer(preserve_case=False)
	
	LEMMATIZER = WordNetLemmatizer()

	# 针对于每一句话抽取aspects
	ASP_EXTRACTOR = 

	def __init__(self):
		

	def word_tokenize(self):
	

	def pos_tag(self):
		

	def lemmatize(self):
		

	def contain_aspect(self):