释义：舌是造成利益或祸害的根本，口是福气祸事之门。

模型的目的是足够简单以便理解和使用，但又足够复杂以捕捉系统的基本特征。

对于非礼的事，上等到的士人根本不想；对于非礼的事，中等的士人从来不说；对于非礼的事，下等的士人紧闭门户。

The great powers are always searching for opportunities to gain power at the expense of rivals, and to dominate the system.

The image is the site of the disappearance of meaning and of the subject, and thus of the disappearance of the scene of the political.

学习数学的最好方法就是做数学。

可持续发展不仅对地球有益，对企业也有益。

A man takes a rocket ship into the stars, and all I got is this broken guitar.