真相很少纯粹，也绝不简单。
The truth is rarely pure and never simple.
Banks exist because they help mitigate problems created by information asymmetries.
The market is a reflection of the economic fundamentals.
拓扑绝缘体的美在于它们的鲁棒性；它们的表面态受到对称性和拓扑的保护，使它们对某些类型的无序免疫。