引用nltk时出现cannot use a string pattern on a bytes-like object

想分割一部英文小说，使用nltk

with open ('AGameOfThrones.txt','rb') as f:
    text = f.read()

此处报错

TypeError: cannot use a string pattern on a bytes-like object

改为

f = open("AGameOfThrones.txt",encoding = "utf-8")

text = f.read()  

cutwords1 = word_tokenize(text)

后成功。