As I mentioned in the Part 1, abstraction and modeling are two key skills.

正如我在第1部分提到的，抽象和建模是两项关键技能。

youdao

This abstraction of implementation details is key to flexibility: it enables you to swap out the implementation type completely without affecting the GUI.

这种对实现细节的抽象是灵活性的关键：它使您能够更换实现类型，而完全不会影响到GUI。

youdao

Two key aspects, the level of abstraction and productivity offered to the developer, as well as the computational completeness and robustness of the language.

两个关键的方面，抽象的水平和给开发人员提供的生产力，以及语言的计算上的完备性和鲁棒性。

youdao

This period culminated in the extraordinary Angel of the Last Judgement, one of the key works of 20th Century abstraction.

BBC: A passion for colour