Compound Sentences (Coordination)

A compound sentence contains two independent clauses—groups of words that can function as complete sentences. The independent clauses in a compound sentence must be separated by a semicolon or by a comma and a coordinating conjunction.

Semicolon

A semicolon can be used to create a compound sentence. A compound sentence is considered a single sentence. Do not capitalize the word that follows a semicolon unless that word is a proper noun.

Two sentences: Lauren went to the mall. Her brother Jamie stayed home.
Compound sentence: Lauren went to the mall; her brother Jamie stayed home.
Compound sentence: Lauren went to the mall; Jamie, her brother, stayed home.

Semicolons are used when two independent clauses have a close relation to one another. Avoid using semicolons with independent clauses that are long or complicated. Also avoid using multiple semicolons in a single paragraph.

Commas and coordinating conjunctions

A compound sentence can also be created by connecting two independent clauses using a comma and a coordinating conjunction.

Example: I went surfing. My sister went snorkeling.
Example: I went surfing, but my sister went snorkeling.

Coordinating conjunctions

The coordinating conjunctions can be remembered by the acronym FANBOYS:

The coordinating conjunction used in a compound sentence defines the relationship between the two clauses.

Example: I did my best. My teacher gave me a B+.
Example: I did my best, and my teacher gave me a B+.
Example: I did my best, but my teacher gave me a B+.
Example: I did my best, so my teacher gave me a B+.

Notice how in the above examples, the coordinating conjunction changes the meaning of the sentence.