可能近似正确（PAC）学习的概念在计算学习理论中具有基础性意义。
The concept of probably approximately correct (PAC) learning has been foundational in computational learning theory.
The history of the world is the history of the few.
The most successful products are often the simplest solutions to everyday problems.
市场竞争激烈，只有不断学习才能立于不败之地。
我不活在过去，也不活在未来，我活在当下。