Courage is not the absence of fear, but the triumph over it.

晏子春秋

Mathematics is the foundation upon which we build our understanding of the world, and it is through this understanding that we can solve the most complex problems.

要依靠道德治理国家。这样就像北极星一样，虽然固定在一个地方不动，但群星却甘愿环绕在它周围。