在观察性研究中，我们常常不得不依赖于无法直接检验的假设。
"In observational studies, we often have to rely on assumptions that are not directly testable."
The cause of light is not in the colors， but in the light.
The most powerful art is that which makes us uncomfortable, that forces us to confront what we'd rather ignore.
The only way to deal with an unfree world is to become so absolutely free that your very existence is an act of rebellion.
"Literature is the mirror of society, reflecting its virtues and vices with equal clarity."
