自古以来，中国就有句老话：“人贵有自知之明。”这一句话暗示给我们，有自知之明并不容易。事实上也确实如此。就拿现在来说，我所见到的人， 大都自我感觉良好，这样的人难有所成。有一句中国老话：“学如逆海行舟，不进则退。”还有一句中国老话：“学海无涯。”说的都是真理。古代希腊人也认为自知之明是可贵的，所以语重心长地说出了“要了解你自己！”中国同希腊距离万里，可竟说了几乎是一模一样的话，可见这些话是真理。中外几千年的思想史和科学史，也都证明了一个事实：只有知不足的人才能为人类文化做出贡献。

As part of human nature, it is not that easy to have a correct self-evaluation. This can be alluded to a time-honored Chinese saying- Rarely will a person has a correct self-evaluation. It is indeed so. Take the people I have met, for example, most of them are complacent about their status quos. But they won’t have some achievements in the long run. Despite the long distance between our two countries, ancient Greeks, who valued self-evaluation and earnestly suggested “Know yourself”, echoed two Chinese old sayings- “Learning is like sailing a boat against current, we should forge ahead or be swept downstream.” and “Learning knows no boundaries. Thus, all these sayings are truths. Histories of thought and science over the past thousands of years both home and abroad have also proved a fact- Only those who are aware of their drawbacks will contribute to the human civilization.