在NLP任务中，常需要分析单词的词性，借助nltk库的pos_tag方法可以较好地实现。

以下是一个例子：

import nltk

line = 'i love this world which was beloved by all the people here'

tokens = nltk.word_tokenize(line)

# ['i', 'love', 'this', 'world', 'which', 'was', 'beloved', 'by',

# 'all', 'the', 'people', 'here']

pos_tags = nltk.pos_tag(tokens)

# [('i', 'RB'), ('love', 'VBP'), ('this', 'DT'), ('world', 'NN'), ('which', 'WDT'),

# ('was', 'VBD'), ('beloved', 'VBN'), ('by', 'IN'), ('all', 'PDT'), ('the', 'DT'),

# ('people', 'NNS'), ('here', 'RB')]

for word,pos in pos_tags: