数学家使用了各种符号来表示不同的变量。

The mathematician used various symbols to represent different variables.

将打印机打印小写字符改变成打印大写字符（及各种符号）。

To change a printer to print upper -case letters(and various symbols) instead of lower-case .

爱国主义始终是美国人的诸多品德当中最为抽象的一种，也许这便是我们对那些有助于定义何谓爱国主义的各种符号争执不休的原因吧。

Patriotism has always been the most abstract of American virtues--which may be why we fight so ferociously over the symbols that help us define it.