1. One should do one's duty.

2. One must do one's duty.

3. Happiness consists in trying to do one's duty.

4. It is easier to do one's duty to others than to one's self.

5. It is seldom very hard to do one's duty when one knows what it is, but it is often exceedingly difficult to find this out.

6. Hard working is the right way to do one's duty.

7. Happiness consists in trying to do one's duty, not in amassing wealth.

8. The divorce where a party failed to perform in accordance with the divorce agreement should do one's duty, other one party can to people court to lodge a civil action.