根据合同条款，他必须履行按时付款的义务。

According to the contract terms, he must fulfill his payment ___obligations on time.

作为父母，我们有义务照顾好孩子。

As parents, we have ___obligations to take care of our children.

我无法参加周末的旅行，因为我有工作上的义务要完成。

I can't join the weekend trip because I have work ___obligations to fulfill.