The past is never dead. It's not even past.
Everything is what it is， and not another thing.
最大的风险是不承担任何风险。
Experience is a good school, but the fees are high.
反馈是鲁棒控制系统的关键。
有记者问：“您的最终理想目标是什么？”张瑞敏回答说。