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Writers' Center

Eastern Washington University

Grammar, Punctuation, and Sentences

The following are very common mistakes related to punctuation usage (or lack of usage).

Comma Splices

A comma splice results when a comma is incorrectly used to join two complete thoughts (meaning each thought has a subject and verb, and the thoughts could stand all on their own—otherwise known as “independent clauses”). Think of it this way: a comma is a weak punctuation mark, and you need something a little stronger to separate two complete thoughts (such as a period or a semicolon—see below for more solutions).

Comma Splice: I had class at 9a.m., I woke up at noon.

Run-On Sentences

A run-on sentence (sometimes called a “fused sentence”) results when two complete thoughts (a.k.a. “independent clauses”) are joined without any punctuation separating them. Hence, your sentence just runs on and on…

Run-On Sentence: I had class early this morning I woke up at noon.

See below for five solutions to your run-on sentence dilemma.

Solutions for Revising Comma Splices and Run-On Sentences:

  1. Separate sentences with a period:

I had class early this morning. I woke up at noon.

  1. Join sentences with a comma followed by a coordinating conjunction:

I had class early this morning, but I woke up at noon.

Side Note: A simple way to remember coordinating conjunctions is to use the acronym FANBOYS (for, and, nor, but, or, yet, so).

  1. Join sentences with a semicolon:

 I had class early this morning; I woke up at noon.

  1. Join sentences with a semicolon followed by a conjunctive adverb:

I had class early this morning; however, I woke up at noon.

  1. Join sentences using a subordinating conjunction:

Although I had class early this morning, I woke up at noon.

Sentence Fragments

Fragments results when an incomplete thought is punctuated as if it were complete sentence.

Sentence Fragment: Down by the bay.

That looks like a complete sentence because it begins with a capital letter and ends with a period, but it is not. It begs the question, what is down by the bay?

Fragments can happen for a lot reasons (maybe there is no subject, maybe there is no verb, or maybe you’ve written a modifying phrase that isn’t actually modifying anything). The previous example could be edited many different ways to achieve a complete sentence, but here’s one example:

Correction: The blue heron landed down by the bay.

Now I have both a subject (“blue heron”) and a verb (“landed”).