incidental

You may incur some incidental expenses on the trip.你在旅途中可能要承担一些附加费用。

an incidental part of the job这项工作的次要部分

an incidental observation顺便观察到的东西

He writes incidental music for plays.他给剧本配乐。

This chapter is incidental to the plot.这一章是配合故事情节而写的。

We received a bill for tuition plus incidentals. [=incidental expenses]我们收到一张附有额外开支的学费账单。

You should bring enough money to cover incidentals like cab fare and tips.你应该带上足够的钱，用以支付打的和小费之类的额外费用。