Independent and Dependent Clauses

When you want to use commas and semicolons in sentences and when you are concerned about whether a sentence is or is not a fragment, a good way to start is being able to recognize dependent and independent clauses.

Independent clause – A group of words that contains a subject and a verb and expresses a complete thought.  An independent is often a sentence.

For example: Jim studied in the Sweet Shop for his chemistry quiz.

There are two types of words that can be used as connector at the beginning of an independent clause:

Coordinating conjunctions – The seven coordinating conjunctions used as connecting words at the beginning of an independent clause are and, but, for, or, nor, so, and yet.  When the second independent clause in a sentence begins with a coordinating conjunction, a comma is needed before the coordinating conjunction.

For example: Jim studied in the Sweet Shop for his chemistry quiz, but it was hard to concentrate because of the noise.

Independent marker word – A connecting word used at the beginning of an independent clause, like also, consequently, furthermore, however, moreover, nevertheless, and therefore. When the second independent clause in a sentence has an independent marker word, a semicolon is needed before the independent marker word.

For example: Jim studied in the Sweet Shop for his chemistry quiz; however, it was hard to concentrate because of the noise.

Dependent clause – A group of words that contains a subject and verb but does not express a complete thought.  A dependent clause cannot be a sentence.

For example: When Jim studied in the Sweet Shop for his chemistry quiz…

Dependent marker words are words added to the beginning of an independent clause that make it a dependent clause such as after, although, as, as if, because, before, even f, even though, in order to, since, though, unless, until, whatever, when, whenever, whether, and while.

For example: When Jim studied in the Sweet Shop for his chemistry quiz…

(Without the word When, this would be a complete sentence and an independent clause; with When, it becomes a dependent clause.  A reader would ask, “When what?”)

Compiled and edited from Purdue Online Writing Lab (OWL).