The present is always an unstable place, the past is where we think we know where we are.

The beauty of language lies in its ability to convey the inexpressible.

Critical comments by students should be taken in a friendly spirit， accumulation of material should not stifle the student’s independence.

The challenge in computer graphics is to simulate the complexity of the real world with the simplicity of mathematical models.

效率能够让你做到你以前不曾做到的事情。

Life is too short to waste time hating anyone.