volunteer

n. /ˌvɑː.lənˈtɪr/ B1

志愿者；自愿参加者

A person who offers to do something without being paid.

仙境例句

When the King asked for a volunteer to taste the tarts, every hand and foot went up.

国王问有没有志愿者来尝尝馅饼，大家的手呀脚呀全都举了起来。