Many writers refer to clauses as the building blocks of language because clauses contain both the topic and action of a sentence. In order for a group of words to earn the classification of a clause, that grouping must contain both a subject and a verb. Clauses are often confused with sentence fragments, which are also comprised of a group of words but lack either the necessary subject or verb.
INCORRECT: The brown dog and his bone. (This group of words is not a clause because it has no verb.)
CORRECT: The brown dog chewed his bone. (This group of words has both a subject and a verb and is therefore a clause.)
Though all clauses must contain a subject and a verb, not all clauses can or have to stand alone. Clauses that can stand alone are called independent clauses. Clauses that cannot stand alone are called dependent or subordinate clauses. Often it is a single marker word like ‘because’ or ‘when’ that prevents a dependent clause from standing alone.
INCORRECT: After the dog got his bone. (The marker word ‘after’ prevents this group of words from standing alone as a logical sentence and therefore designates them as a dependent clause.)
CORRECT: The brown dog chewed his bone. (This group of words has both a subject and a verb and makes perfect sense as is, making it an independent clause.)
As their name implies, dependent clauses must appear with an independent clause in a sentence in order for them to make sense. You can also connect two independent clauses in a single sentence by using coordinating conjunctions such as ‘or’, ‘and’, ‘but’ or ‘for’. Without a conjunction or other marker word connecting clauses, the resulting sentence is a run-on.
Learn all about independent and dependent clauses, from what defines each clause to how to correctly use and combine them.