The answer is 1: He runs the mile like a run on free soda at the fair.
He runs- verb: to run (to race, to hurry, to rush)
a run - noun: run (drive, ride, trip)
Sentence 2: noun: fork (a place where a road, river etc divides into two parts, or either of two parts.)
Sentence 3: adjective: impervious (not allowing liquid to go through; not able to be influenced, hurt, or damaged.)
Sentence 4: adjective: inviolate (that must be not harmed or damaged.)