题目内容：

商务英文翻译
Revenue: Result from the sales of products or service for a period of time.
Expense: Costs incurred to generate revenues for a period of time.

优质解答

收入：来源于一段时间内的产品或服务销售
费用：一段时间内为产生收入而发生的成本

追问：

请问incur为什么要加ed？

追答：

costs incurred = costs that have been incurred,我是这样理解的，不知对否