1.84. Tim and Greg were talking. Tim said "The terror of flight." Greg said "The gloom of the grave." Greg was arrested. (MPW original, from "No Refuge Could Save," by Isaac Asimov)
1.84 answer: The setting is America during WWII. Greg is a German spy. His "friend" Tim is suspicious, so he plays a word-association game with him. When Tim says "The land of the free," Greg responds with "The home of the brave." Then Tim says "The terror of flight," and Greg says "The gloom of the grave." Any U.S. citizen knows the first verse of the national anthem, but only a spy would have memorized the third verse. (Why Tim knew the third verse is left as an exercise to the reader.)