1. I know Bob.
How long have you known Bob?
2. Sue and Alan are married.
How long have Sue and Alan been married?
3. George is unemployed.
How long has George been unemployed?
4. Those books are here.
How long have those books been here?
5. Mary is at the airport.
How long has Mary been at the airport?
6. My sister is ill.
How long has your sister been ill?
7. She has got a bad cold.
How long has she had a bad cold?
8. Jan has long hair.
How long has Jan had long hair?
9. I have a yacht.
How long have you had a yacht?
10. They are in the restaurant.
How long have they been in the restaurant?
11. My parents are in London.
How long have your parents been in London?
12. The cat is under the table.
How long has the cat been under the table?