有时候可数有时候不可数,具体如下：
可数：生意,商业,行业
she started a new business in L.A.
不可数：职责,本分,分内事
it's none of your business.
榜样：example
例句：Comrade Lei Feng left an undying example behind.雷锋同志留下了一个不朽的榜样.
树立榜样：set an example
欢迎追问,go on business 出差所以填【business】