The Liskov Substitution Principle is a fundamental concept in object-oriented programming, ensuring that derived classes can be used in place of their base classes without altering the correctness of the program.

The biggest risk is not taking any risk.

人的精神本喜欢清净，但被心所扰乱；人心本喜欢宁静，但被欲望所牵引。

【解释】幸福不可强求，保持愉快的心情，更能感受到幸福；灾祸难以避免，消除怨恨他人的念头，就能远离灾祸。