Conjunctions are words that join two or more words, phrases or clauses. The most common conjunctions include; and, or, but. Conjunctions are often used to join sentences together. The word "and" shows addition. The word "or" shows an alternative. The word "but" shows a contrasting idea. These common conjunctions are used in the texts you read and the sentences you write. They join sentences and ideas together so the writing and reading can flow smoothly. Use our conjunctions worksheets below to learn all about conjunctions.