A flat tax is an example of a proportional tax.

单一税就是比例税的一个例子。

They argue a flat tax isn't as simple or as fair as it seems.

他们认为单一税并不像看起来那么简单和公平。

Economists who oppose the flat tax say that feelings have no place in the tax code.

反对单一税的经济学家说，税法没有感情。