n.义务；责任
We are invited, but we are under no obligation to go. 我们是被邀请了,但并不意味着我们有义务一定要去。
Some people suggest that the old people's children have the obligation to look after their old parents. 一些人认为：老年人的子女有义务照看他们的父母。
n.义务
名词obligation的复数形式.
