动力学的方程在用变分法的语言表达时是完全的。

过去不是一个地方，而是一种状态。

【释义】选择人生道路与奋斗目标时，应当直接坚定、不绕弯路；帮助他人、提出建议时，应当委婉含蓄、顾及对方感受；谋划重要事情时，应当谨慎保密、避免泄露；对待他人相处时，应当宽厚包容、不计小节。

I've always been interested in art and making things, but I chose not to go to art school because I thought I needed to do something else. Art was a tough way to make a living. I've always done both. I just kind of figured that the marine biology would be a career and the art would be something I did for my own self-expression.

绝不能为了短期利益而牺牲质量。