... 自愿的，随意的：voluntary 自愿参加者：volunteer participant 自由支配所得：discretionary income ...
双语例句
1
As an active participant in various volunteer work, I have a lot of experience in serving others.
作为一个积极参与各种志愿活动的人，我在服务他人方面有很多经验。
2
A child participant paints a doll with the help of a volunteer.
孩子参与者描绘的洋娃娃的帮助一名志愿者。
3
We would like to express our sincere appreciation to all of you, either as a co-sponsor, contributor, performer, volunteer, or as a participant of the Celebration.