volunteer既可以作名词，表示“志愿者”；也可以作动词，表示“资源做；无偿做”等含义。volunteer是可数名词，表示是某个组织的志愿者时，通常用“a volunteer with+组织名称”结构。
1.作名词
(1)They are retired and working in the organization as volunteers.
他们已经退休了，在那个组织里做志愿者。
(2)As a volunteer with the Little Village Environmental Protection Organization,she went door to door talking about the dangers of pollution.
作为“小村庄环境保护组织”的志愿者，她挨家挨户地给人们讲污染的危害。
(3)He worked as a volunteer teacher in this school to help the poor children.
他在这所学校任志愿教师，以帮助这些穷困的孩子。
2.作动词
(1)He was always the first to volunteer for such tasks.
他总是第一个自愿做这样的任务。
(2)She worked in a restaurant and also volunteered for teaching dance classes at night.
她在一家餐厅工作，也再晚上自愿教授舞蹈课程。
(3)Over thirty thousand people have volunteered to help out.
超过三万人自愿进行了帮助。
(4)My brother volunteered to play the guitar and sing a song at the school party.
我滴滴自愿在学校晚会上弹吉他、唱歌。
3.常用搭配
volunteer for sth./doing sth.表示“志愿/自动申请某事；志愿/自动申请做某事”。
Volunteer to do sth.表示“自愿/义务/无偿做某事”。
