Prepositions are words that link nouns, pronouns, and phrases to other words in a sentence. There are prepositions of place that indicate location like "in" and "on", prepositions of time like "during" and "before", and prepositions of direction like "down" and "along". Conjunctions link words, phrases, and clauses. The main types are coordinating conjunctions like "and" and "but", and correlative conjunctions that come in pairs like "either/or". Articles are "a", "an", and "the". "A" and "an" are indefinite articles used with nouns being introduced. "The" is the definite article used when the