Complete the sentence: If he had studied, he _____ passed.

The correct completion for the sentence "If he had studied, he _____ passed" is would have. This sentence structure exemplifies the third conditional in English grammar. The third conditional is used to talk about hypothetical situations in the past that did not happen, and their imagined results or consequences. It describes an unreal past condition and its unreal past result. The structure typically follows the pattern: "If + subject + past perfect (had + past participle), subject + would have + past participle." In this specific sentence, "If he had studied" represents the unreal past condition (he did not study), and "he would have passed" represents the unreal past result (he did not pass). This grammatical construction allows speakers to express regret, criticism, or simply to speculate about how things might have been different if a past event had occurred differently.