我们需要为自己想要的事物而奋斗，因为生活并没有义务要给予我们所期待的东西。

We should fight for what we want because life is under no obligation to give us what we expect.

youdao

选民实在是没有义务要受这样的欺骗。

Voters are under no obligation to be so gullible.

youdao

小费罐，根据告示是没有义务给的。

Tip jars, according to Post, carry no obligation.

youdao

But nobody says, "Arrest that man, he has broken his debt; he's not performing his debt to the community."

他们不会说,"逮捕他,他违背了他的义务,他没有对他的集体履行义务"

耶鲁公开课 - 古希腊历史简介课程节选

So you don't think the idea of implied consent is strong enough to generate any obligation at all to obey the government?

就是说你认为默认同意的观点,并没有强到，足以让人有服从政府的义务？

耶鲁公开课 - 公正课程节选

If you're wondering what's OK or what's not OK, it's very clearly written out in this handout, so make sure you read through it, because it is your responsibility to make sure that your calculator does not have anything extra programmed in it.

如果你不清楚什么可以什么不可以，讲义上写得很清楚，所以请大家务必看完它，因为你有义务保证,在自己的计算器里,没有编上额外的程序。

麻省理工公开课 - 化学原理课程节选