To chyba powinno być jakoś tak:
1. Ten people applied for the job, none of them were suitable
Ten people applied for the job, none of them was suitable.
po polsku też tak jest - inaczej brzmi żaden z nich nie byli odpowiedni.
2. When I was walking home, there was a man who was following me.
When I was walking home, there was a man who following me. - inaczej jest masło maślane
3.No, even his wife doesn't know where Peter has gone.
No, even his wife doesn't know where has Peter gone. -to chyba powinno być tak - to jest jak reported speech