父母有义务照顾自己的孩子。

Parents have an ___obligation to take care of their children.

根据协议，我们有义务在月底前支付租金。

Under the agreement, we have an ___obligation to pay the rent by the end of this month.

收到这份珍贵的礼物后，他深感有义务回报对方的好意。

After receiving this precious gift, he felt a strong ___obligation to return the kindness.