Replace the of-phrase by the noun in the possessive case.
1. The friend of my mother.
2. The speech of the President.
3. The farm of old McDonald.
4. The novels by D. Steel.
5. The hobbies of the children.
6. The poems by Burns.
7. The duties of a man.
8. A conference of doctors.
9. The life of a bodyguard.
10. The policy of France.
11. The streets of London.
12. The bank of the river.
13. The rays of the sun.
14. The way of nature.
15. The teas of India.