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1. Hiccups happens/happen when your diaphragm (DAHY-uh-fram) twitches. Your diaphragm is a muscle that helps you breathe. Even though hiccups is/are usually harmless, they can be annoying!
2. Humans has/have wondered about hiccups for thousands of years. In the Middle Ages, people in Europe thought that hiccups were the work of evil elves.