We cannot usually use a possessive word before another determiner and a noun. We can say my cat, their cat, a cat or that cat, but not a my cat or that my cat. Instead we use a structure with of + possessive.
Word order: determiner + noun + of + possessive
- He is a friend of mine. (NOT He is a my friend.)
- She is a colleague of my father’s. (NOT He is a my father’s colleague.)
- Have you heard this new idea of the boss’s?
- He got the President’s Award for a painting of his.
- A cousin of mine serves in the army.
- He is a cousin of the Minister.
Own is commonly used in a similar structure.
- I wish I had a car of my own. (= I wish I had a car of mine.)
- They have an apartment of their own in the city. (= They have an apartment of theirs in the city.)
The of + possessive structure is sometimes used to express slight contempt or indignation.
- That cat of yours has drank up all the milk.
- Those dirty fingers of yours have stained my walls.
- That boy of yours has broken my window again.