1. You must take care of your health.
2. We must obey the laws of our country.
3. He must obey his teacher.
4. We ought to die sooner or later.
5. Walk carefully lest you fall down.
6. You should start your work in right earnest.
7. One must love one's neighbour.
8. You must not give way to despair even if you fail once.
9. The Bursar should check all the accounts.
10. Students must prepare their lessons well.
11. The doctor told me that I have to do as we are told.
12. We must not smoke any more.
13. Children must obey and respect their elders.
14. The headmaster must be in school at eight.
15. You must not squander your parent's hard earned money.
16. You ought to mend your own ways before you criticize others.
17. The students must be in school at eight.
18. You must not disobey the laws of the land.