Understand the definition of a compound sentence. A compound sentence joins two complete clauses (complete sentences) into one sentence. Each side of a compound sentence is a complete thought, and each has equal weight and importance.
Know how to use coordinating conjunctions in compound sentences. The two clauses of a compound sentence can be joined by a coordinating conjunction. Coordinators include for, and, nor, but, or, yet and so. To make the compound sentence grammatically correct, place a comma before the conjunction.
Be familiar with how to choose a coordinating conjunction. The most commonly used conjunctions for compound sentences show the relationship between the two parts of the sentence. "And" connects two independent clauses that contain the same type of idea. "So" is used when the second part of the compound sentence shows a result or outcome. "But" shows that the second part of the sentence has the opposite idea from the first. "Or" designates two clauses that illustrate equal choices.
Be aware of other options for creating a compound sentence. You can create a compound sentence without using a coordinating conjunction. Instead, substitute a semicolon for the coordinator as a way to designate the two independent clauses. Another option is to use the semicolon and follow it with a conjunctive adverb. Examples of conjunctive adverbs are otherwise, thus, nevertheless, however or therefore. Place a comma after the conjunctive adverb.
Recognize how to separate the ideas in a compound sentence. Changing a single compound sentence into two sentences is easy because each section is an independent clause. Break a compound sentence into separate sentences by putting a period after each independent clause.
Know how to recognize grammatical errors in a compound sentence. The most common grammatical errors associated with compound sentences are comma splices and run-on or fused sentences. A comma splice is when the independent clauses in a compound sentence are separated only by a comma. A run-on or fused sentence has no punctuation or coordinating conjunction to join the clauses.