自愿optional;voluntary;of one’s own accord;of one’s own free will
出于～on a voluntary basis;of one’s own free will/根据～的原则on a voluntary basis/自觉～ voluntarily;willingly;of one’s own free will/～互利的原则principle of voluntary participation and mutual benefit/～捐献volunteer a donation/～遣返voluntary repratriation/～提供服务volunteer one’s services /～退出opt out /～献血者volunteer donors of blood /～组织起来voluntary self-organization/～做某事volunteer to do sth /～者volunteer |