假设有一个多字符的片断重复出现，把"really"、"really really "，以及任意数量连续出现的"really"字符串换成一个简单的"very ” ( Billy tried really hard Sally tried really really hard Timmy tried really really really hard Johnny tried really really really really hard )

将这个字符串中的重复出现的"really"字符串替换成一个简单的"very"字符串，可以使用正则表达式来实现。具体的实现方式如下：

import re

text = "Billy tried really hard Sally tried really really hard Timmy tried really really really hard Johnny tried really really really really hard"
pattern = r"\b(really\s+)+"
replacement = "very "

result = re.sub(pattern, replacement, text)

print(result)

输出结果为：`Billy tried very hard Sally tried very hard Timmy tried very hard Johnny tried very hard`。