学习XX就是学习XX他爸他妈
这里把XX替换为【概念】，那【XX他爸】就是概念的属概念，【他妈】就是概念的部概念。
以CSS 为例子，以下是CSS在维基百科中的相关条目简要描述：
Cascading Style Sheets (CSS) is a style sheet language used to describe the presentation semantics of a document written in a markup language.
# A style sheet language or style language, is a computer language used to describe the presentation of structured documents.
##A programming language is an artificial language designed to express computations that can be performed by a machine, particularly a computer.
##A structured document is an electronic document where some method of embedded coding, such as markup, is used to give the whole, and parts, of the document various structural meanings according to a schema.
#In computer science, particularly in human-computer interaction, presentation semantics specify how a particular piece of a formal language is represented in a distinguished manner accessible to human senses, usually human vision.
#A markup language is a modern system for annotating a text in a way that is syntactically distinguishable from that text.
CSS他爸包括【style sheet language】，他爷【programming language】；
他妈是【structured document】和【presentation semantics】，还有【markup language】等。
另外由这个例子可知，学习XX为何如此困难和耗时（以下CSS可替换为任何XX）：
首先，很难对CSS进行完备描述；
其次，无须对CSS进行完备了解即可作业，达到【基本】就够，当然越完备越好；这里取决于达到什么级的能力，比掌握与精通；
第三，掌握CSS等于掌握CSS 的上位概念（属概念）之和，还有CSS的【部概念】之和；这也说明了为什么研究一种事物的首要是研究它的历史，因为某事物的历史事实就是对该事物的属概念和部概念进行阐述；
第四，由第三是到得为何精通甚至只是掌握CSS技术都很费时的原因，因CSS的大部分属概念和部概念都很耗时间。
以CSS 为例子，以下是CSS在维基百科中的相关条目简要描述：
Cascading Style Sheets (CSS) is a style sheet language used to describe the presentation semantics of a document written in a markup language.
# A style sheet language or style language, is a computer language used to describe the presentation of structured documents.
##A programming language is an artificial language designed to express computations that can be performed by a machine, particularly a computer.
##A structured document is an electronic document where some method of embedded coding, such as markup, is used to give the whole, and parts, of the document various structural meanings according to a schema.
#In computer science, particularly in human-computer interaction, presentation semantics specify how a particular piece of a formal language is represented in a distinguished manner accessible to human senses, usually human vision.
#A markup language is a modern system for annotating a text in a way that is syntactically distinguishable from that text.
CSS他爸包括【style sheet language】，他爷【programming language】；
他妈是【structured document】和【presentation semantics】，还有【markup language】等。
 |
另外由这个例子可知，学习XX为何如此困难和耗时（以下CSS可替换为任何XX）：
首先，很难对CSS进行完备描述；
其次，无须对CSS进行完备了解即可作业，达到【基本】就够，当然越完备越好；这里取决于达到什么级的能力，比掌握与精通；
第三，掌握CSS等于掌握CSS 的上位概念（属概念）之和，还有CSS的【部概念】之和；这也说明了为什么研究一种事物的首要是研究它的历史，因为某事物的历史事实就是对该事物的属概念和部概念进行阐述；
第四，由第三是到得为何精通甚至只是掌握CSS技术都很费时的原因，因CSS的大部分属概念和部概念都很耗时间。
