1. This is very urgent, please keep on ... it.

2. This is a secret between you and me, you should keep it …

3. Adults should keep their children ... playing with fire.

4. This knowledge is very important, please keep it in …

5. You are so annoying, why do you keep on at me ... this issue?

6. We kept ... during the 3-month summer vacation.

7. Keep your … crossed! You will finish this project smoothly.

8. I keep a … that I will return this money to you tomorrow.

9. If you don’t keep the …, you can be punished.

10. Please keep this secret ... my brother, I don't want him to know about it.