“فَ” (fa)This word resumes the flow after a pause or change in thought.Corpus grammarREM — prefixed rem particle.
“بِ” (bi)means “in / with / by.” It is a preposition: it links this word to the next word or phrase.Corpus grammarP — prefixed preposition.
“أَىِّ” (ʾaāi)means “Then which (of)” in this verse. It is a noun. a naming word. Here it is genitive.Corpus grammarN — genitive noun.