Skip to main content
It looks like you're using Internet Explorer 11 or older. This website works best with modern browsers such as the latest versions of Chrome, Firefox, Safari, and Edge. If you continue with this browser, you may see unexpected results.

Center for Writing and Academic Achievement: Grammar

A general guide to common questions about writing and grammar

Purdue OWL

The Purdue OWL Online Writing Lab is a great resource for answering grammar questions! 

To access the OWL,  click on the above icon. Type the subject in question into the search bar to view instructive guides and samples exercises.

Common Grammar Issues

Comma Splice: A comma splice occurs when a comma is incorrectly used in place of more forceful punctuation to join two or more independent clauses. An example of a comma splice is the sentence: I want to do well in school, my parents will be happy. Both “I want to do well in school” and “my parents will be happy” are independent clauses that could exist as their own sentence. When a comma splice occurs, replacing it with a period or semicolon, or rewording the sentence can fix the problem. For example, the previous example sentence could be fixed by saying: I want to do well in school. My parents will be happy. It could also read: I want to do well in school; my parents will be happy. Lastly, the sentence could be rewritten to say: If I do well in school, my parents will be happy. In this instance, “my parents will be happy” is still an independent clause, but “if I do well in school” is a dependent clause; therefore, since they could not be two separate sentences, this is not a comma splice.

Run-on sentence: Like a comma splice, a run-on sentence combines two or more independent clauses without proper punctuation. The sentence: I want to do well in school my parents will be happy is an example of this type of error. The solutions for fixing a comma splice, listed above, also work for this type of mistake. Also, a long sentence is not necessarily synonymous with a run-on sentence, so it is important to differentiate between the two.

General Comma Usage: There are many appropriate instances to use a comma. Commas should be used to separate items in a list consisting of three or more items and placed before introductory phrases. They also are used with conjunctions, such as but, and, etc., and to set off additional pieces of information in a sentence.  For example, consider the sentence: Joanna, who is on the track team, completed a marathon this weekend. Commas are necessary here because “who is on the track team” is not a piece of crucial information to the sentence, but rather a secondary thought. Commas are also used to separate multiple adjectives that describe the same noun (ex. The tall, redheaded girl).  Consult a handbook for a more detailed review of comma usage

Semicolon: Semicolons are one type of punctuation that can be used to link two independent clauses together. They are used when no connecting word (and, but, etc.) exists and with conjunctive adverbs (however, moreover, etc.,). For example, a semicolon is appropriate in the next sentence because it does not have a word that connects the two independent phrases: I bought a new book; I love to read.

Active/Passive Voice: The active voice occurs when the subject performs the action described by the verb. An example of an active voice sentence is: I watched the Red-Sox game. The passive voice occurs when the subject is being acted upon by the verb. An example of a passive voice sentence is: The Red-Sox game was watched by me. In general, it is much more concise and effective to use active voice. However, some types of writing, especially writing in the sciences, require using the passive voice.

Suggested Books

Login to LibApps Noice of Web Accessibility