My brother has been working at the factory since 1999.
1 Has your brother been working at the factory since 1999?
2 My brother has been working at the factory since 1999, hasn't he?
3 Who has been working at the factory since 1999?
4 Has your brother been working at the factory since 1990 or 1999?
5 Where has your brother been working since 1999?