1. he’s teacher since September. How long has he been a teacher? Since September.
2. My parents work in a shop since 1992. How long have they worked in a shop? since 1992.
3. My sister knows Robbie Williams for six months. How long has she knew Robbie Williams? for six months.
4. We’ve got a new car for two weeks. How long have you got a new car? for two weeks