Rules for writers, Tenth edition - Diana Hacker, Nancy Sommers 2021
Consider separating the clauses with a comma and a coordinating conjunction
Revise run-on sentences
Grammar
✵ ► How to revise a run-on sentence
Run-on sentences are independent clauses that have not been joined correctly. An independent clause is a word group that can stand alone as a sentence. (See 50a.) When two independent clauses appear in one sentence, they must be joined in one of these ways:
✵ with a comma and a coordinating conjunction (and, but, or, nor, for, so, yet)
✵ with a semicolon (or occasionally with a colon or a dash)
The chart on the next page will help you recognize run-on sentences in your writing. The box on page 175 will help you revise them.
Recognizing run-on sentences
There are two types of run-on sentences. When a writer puts no mark of punctuation and no coordinating conjunction between independent clauses, the result is called a fused sentence.
A far more common type of run-on sentence is the comma splice — two or more independent clauses joined with a comma but without a coordinating conjunction. In some comma splices, the comma appears alone.
In other comma splices, the comma is accompanied by a joining word that is not a coordinating conjunction. There are only seven coordinating conjunctions in English: and, but, or, nor, for, so, and yet.
However is a transitional expression and cannot be used with only a comma to join two independent clauses (see 20b).
RECOGNIZING RUN-ON SENTENCES
HOW TO
Revise a run-on sentence
To revise a run-on sentence, you have four choices.
1. Use a comma and a coordinating conjunction (and, but, or, nor, for, so, yet).
2. Use a semicolon (or, if appropriate, a colon or a dash). A semicolon may be used alone; it can also be accompanied by a transitional expression.
3. Make the clauses into separate sentences.
4. Restructure the sentence; try subordinating a clause.
One of these revision techniques usually works better than the others for a particular sentence. The fourth technique, the one requiring the most extensive revision, is often the most effective.
20a Consider separating the clauses with a comma and a coordinating conjunction.
There are seven coordinating conjunctions in English: and, but, or, nor, for, so, and yet. When a coordinating conjunction joins independent clauses, it is usually preceded by a comma. (See 33a.)