Complete the sentences with the correct form of say or tell.
1. Have you ever told a joke where no one laughed?
2. She never .... goodbye when she leaves the house.
3. I can't .... the difference between these computers.
4. I crashed my bike into the wall and my dad really ...me off.
5. It's never too late to .... sorry.
6. He didn't even .... thank you for the present.