Complete the sentence with the correct form of the verb in brackets: The rare call went unverified last Tuesday. If the sound engineer ___ it, the ornithologists would have confirmed the species. (record)
الإجابة الصحيحة
had recorded
الشرح
Had recorded places the unreal recording before the confirmation that never happened. Recorded alone does not supply the past-perfect condition required for a counterfactual entirely in the past.