Change into passive voice :
'They are following us'.
Awe are followed by them
Bwe have been followed by them
Cwe are being followed by them
Dwe were being followed by them
Change into passive voice :
'They are following us'.
Awe are followed by them
Bwe have been followed by them
Cwe are being followed by them
Dwe were being followed by them
Related Questions:
Change into Passive Voice :
Let him complete the food.