很多已经掌握了一门编程语言并想学第二门语言的开发者常常发现学习第一门语言很难，但是接下来的语言都简单的多。
Many developers who know a particular programming language and want to learn a second one, often find it the hardest language to learn but subsequent languages being easier.
想学习编程，你就该写一些比较复杂的程序。
To learn about programming, you need to write some fairly complex programs.
如果你是Python 3的初学者且是专门搞面向对象编程，或者你想学习一些编程模式，我推荐给你这本书。
If you're new to Python 3 and specifically object oriented programming or you want to learn about programming patterns, I recommend this book.
应用推荐