demonstrator

1. N-COUNT Demonstrators are people who are marching or gathering somewhere to show their opposition to something or their support for something. 游行者; 集会示威者

I saw the police using tear gas to try and break up a crowd of demonstrators. 我看到警察使用催泪瓦斯试图驱散示威人群。

2. N-COUNT A demonstrator is a person who shows people how something works or how to do something. 展示者

...a demonstrator in a department store. …一名百货商场的产品展示员。