فَأَيْنَ تَذْهَبُونَ
Sentence structure
أَيْنَ is an interrogative locative adverb. تَذْهَبُونَ is a second-person plural imperfect of the five verbs: its penultimate و is the subject and final ن marks the indicative.
Ayah summary
After these clear proofs, where are you going by turning away from the truth?
فَأَيْنَ — So where
Grammar: فَ resumes or draws an inference; أَيْنَ is an accusative interrogative locative adverb.
تَذْهَبُونَ — are you going
Grammar: A second-person masculine plural imperfect of the five verbs. The penultimate و is wāw al-jamāʿah and the subject; the final ن is the indicative marker of the five verbs.