Preposition bâ (Instrumental case)

The preposition marks the instrumental case which expresses: means, accompanying

châghu az khodash defâø kardshe defended herself with a knife
bâyad ghâshogh khord-ashyou have to eat it with a spoon
dustpesar-ash zendegi mikonadshe lives with her boyfriend
dishab pedar-am telefoni harf zadamLast night I talked to my father by phone
mâshin raftanto go by car
dastby hand
medâdin pencil