1. What boots would you like to buy?
    The black ones.
2. A fireman's job is a very difficult one.
3. I've lost my ruler
    What kind of ruler?
    It's a metal one.
4. She laughed at the silly stories and tried to write a better one.
5. May I ask you some questions?
    Sure. I hope they are easy ones.
6. There were large boats with eight or ten people, and small ones with two or three people.
7. How much are the apples?
    The green ones are very cheap.
8. Don't you have a cheaper ball?
    No, I'm afraid not. This is the cheapest one we have.
9. What kind of blouse do you want?
    A silk one .
10. What books shall I bring?
     The interesting ones.