义务既compulsory又voluntary的意思吗？义务是什么意思? 今天上课的时候我遇到这个单词“义务”： 义务 津贴（义务兵）（职业兵） 有。。。义务 （责任） 义务：义务植树，义务种树，义务活动，义务献血 （自愿） 义务教育，尽义务 compulsory？voluntary？duty? donation? 例子和翻译都从百度词典来的： 比如说：你有义务照顾她 = You are under obligation to care for her. 比如说：她从事义务社会工作。=She does voluntary social work. 比如说：政府号召青年义务献血。 = The government calls on the youth to donate their blood voluntarily. 按照pleco和百度词典：[duty;obligation;commitment] and [volunteer;voluntary] compulsory 百度词典：必须做的;义务的;必修的 谢谢你们。可能义务voluntary的意思是（免费的）do something for free? like a donation. 比如：it's your duty to donate. it's your obligation to donate your time (by volunteering it). According to the english translations it looks like the term 义务 contradicts itself. Because the opposite of voluntary is obligatory. the question is WHAT does this term mean and HOW can it be voluntary and obligation can be used at the same time?是矛盾吗？