The document discusses different ways to express possession in English:
1) Possessive nouns show possession using an apostrophe and "s" (e.g. Mary's car).
2) Possessive adjectives are formed by adding "my", "your", "his", "her", "its", "our", or "their" before a noun (e.g. her car).
3) Possessive pronouns are used instead of repeating a possessive adjective (e.g. hers is old instead of her car is old).