5
No, they aren't.
Yes,he is.
No, I don't.
Yes,he does.
No, he hasn't.
No, I haven't.
6
1. How long have you known Sasha?
2. How long have you been studying English?
3. We have known each other since 1993.
4. Natalie has been working in the mall for three months.
5. Natalie has been taking driving lessons for seven months.
6. Joey and Sasha have been friends for several weeks.