don't agree 看看教科书，学个技能，相当于“打渔”； this is also 悟

don't agree with those too. 但是教科书缺乏理论的历史背景，断裂了逻辑上的来龙去脉，隐瞒了理论本身的必须假设和适用局限。所以，只有历史的去研究，看原著，才能了解理论的历史背景，逻辑上的来龙去脉，以及理论本身的必须假设和适用局限。看原著，为的就是一个悟

Chinese text books few pages. America text books, a lot of pages. original books, if you really understand, you are 天才 or close to 天才. this is what you said 悟. most people in this world (include me) don't have this IQ to do it.