NLP : Rules for chunking Verb Phrases
There are many ways to perform chunking/phrase structure parsing. The most common methods are:


Rule-based
Statistical models
Deep Learning


Fixed rules are simple and fast. But they make many mistakes given the complexity of human language. The other methods are typically more useful because they generate probabilistic rules.

Context-free grammar (CFG) is a set of rules for the production of formal language and can be used for parsing.