To master a language, words, and grammar rules are not enough. You must do a lot of reading.
What is language for? Some people seem to think it is for practicing grammar rules and learning lists of words — the longer the words the better.
But that simply doesn't work: The idioms, grammar rules, and cultural differences make text written in this manner sound clumsy and unnatural.
My .p_para() should contain only a set of grammar rules in its docstring (no code).
This book focuses on grammar and exercises, allowing the learners to master grammar rules through exercises.
Reason underlying the similarity is that there is acquisition mechanism in human mind, which can internalize the grammar rules.
You can chose from a number of different standards and methods to specify the grammar rules: One is based on a text format, the other an XML specification.
Some people seem to think language is for practicing grammar rules and learning lists of words. That's wrong. Language is for the exchange of ideas, for communication.
