The unit, written by Pierre Peterson, describes a system for teaching the main parts of speech that will absolutely work with students who are at least fluent in spoken English. It involves replacing an unknown part of speech with a common word that is unlikely to be misused by any fluent English speaker. The whole process can be taught in a single class period so that the student can understand and correctly use a given part of speech in a sentence. The unit also includes foolproof mnemonic devices for prepositions and conjunctions. It also includes practice exercises.