2 What is a Comma?,A comma is a punctuation mark that indicates a pause is needed in a sentence.Commas help to clarify meaning for the reader.Key Concepts: The facilitator may choose to invite the audience to respond to the title question and allow participants to discuss the function of the comma. Many writers become frustrated with comma usage because they are unsure of where to place them in their sentences. This presentation is designed to demystify the placement and usage of commas.The facilitator may stress to participants that commas should not be ignored in writing; they are often needed to clarify meaning within a sentence and can help to avoid confusion.Click mouse after title question to reveal each response.
3 Clauses and PhrasesA clause is a group of words that contains both a subject and a verb that complement each other.A phrase is a group of words that does not contain a subject or a verb that complement each other.ClausesDependentIndependentKey Concepts: This slide articulates the basic differences between a clause and a phrase. The facilitator may stress the importance of understanding these definitions for understanding comma placement.
4 Sentence Structure: Independent Clauses A complete sentence has at least two components, a subject and a verb.The subject and verb must form a complete thought to be considered an independent clause.Key Concepts: This slide explains the structure of an independent clause, the primary building block for the development of any sentence. An independent clause requires a subject and a verb that can stand as a complete thought. Sentences can be very short, as the one detailed in the slide. The facilitator may ask the audience to identify the subject and verb in the example.
5 Sentence Structure: Compound Sentences Compound Sentence: a sentence that contains two independent clauses joined by a coordinating conjunctionA conjunction joins words, phrases, and clauses together in a sentence.Conjunctions (remember with the acronym FANBOYS):Key Concepts: This slide explains the structure of a compound sentence and the role of a conjunction. An easy method for remembering the seven coordinating conjunctions is the acronym “fan boys.”
6 Sentence Structure: Compound Sentence The comma in a compound sentence is placed before the coordinating conjunction.Example: This slide exemplifies the location of a comma in a compound sentence, before the coordinating conjunction. The facilitator may ask participants to identify the subjects, verbs, and conjunction in the example.
7 Sentence Structure: Compound Sentence Where would you place the comma in the following sentence?Example: This slide provides participants with an opportunity to locate the correct position for the comma within the sample sentence. The facilitator may also invite students to identify the subjects, verbs, and conjunction in the sentence.
8 Sentence Structure: Dependent Phrases A dependent clause contains a subject and verb, but the clause cannot stand independently.Dependent clauses can often be identified by the use of dependent clause markers:Key Concepts: This slide explains the definition of a dependent clause. The dependent clause markers can help writers identify clauses that cannot stand alone within a sentence.
9 Sentence Structure: Dependent Phrases Dependent phrases and clauses help to clarify and add detail to an independent clause.Dependent clauses may appear at the beginning, middle, or end of a sentence.Key Concepts: This slide further clarifies the role of dependent phrases and clauses within a sentence.
10 Sentence Structure: Introductory Clauses When a dependent clause is placed at the beginning of a sentence, place a comma between the independent clause and the dependent clause.Key Concepts: An introductory clause is a dependent clause located at the beginning of a sentence. After an introductory clause, a comma is needed to distinguish it from the independent clause.Activity: The facilitator may choose to ask students to identify the independent and dependent clauses, the subjects, the verbs, and the dependent clause marker in the sample sentence.
11 Introductory ClauseWhere would you place the comma in the following example?Activity: Click to reveal answer.
12 Dependent ClausesWhen a dependent clause is located after an independent clause, do not place a comma between the two.Activity: When a dependent clause follows an independent clause, commas are not used. Facilitators may choose to ask students to identify the parts of speech in the example.
13 Essential Phrases and Clauses An essential clause or phrase is used to modify a noun. It adds information that is critical to the meaning of the sentence.Essential clauses are not set off by commas.Key Concepts: This slide leads off a section about essential and non-essential phrases and clauses. Essential phrases and clauses—elements that add critical information to the meaning of a sentence—do not have commas placed around them. For the slide example: Without the essential phrase, this sentence does not make complete sense : The people are loud! While the sentence is grammatically correct, we don’t know about the people being discussed.
14 Essential Phrases and Clauses The word “that” is almost always an indicator of an essential phrase or clause.Key Concept: The word “that” almost always indicates an essential phrase or clause.
15 Non-essential Phrases and Clauses A nonessential clause or phrase adds extra information to a sentence. This information can be eliminated from the sentence without influencing the meaning of the sentence.Always place commas around nonessential phrases and clauses.Key Concepts: This slide illustrates the difference between essential and nonessential elements. While commas should not be placed around essential phrases and clauses, they should be placed around nonessential phrases and clauses.
16 Non-essential Phrases and Clauses Use commas to set off additional information:Example: This slide provides another example illustrating the placement of a nonessential phrase within a sentence. At the end of a sentence, the nonessential element should have a comma placed before it and a period after it. The facilitator may wish to stress that “which” often, but not always, indicates a nonessential phrase or clause.
17 Comma PracticeWould you place commas in the following sentences? If so, where?I am planning a trip to Paris which is one of the greatest cities in the world.The place that I would most like to see is the Eiffel Tower.Pierre, who is one of my business contacts, will meet me at the airport.Activity: These examples allow participants an opportunity to test their comma skills.The first example needs a comma after “Paris” to set off the nonessential phrase.The second example requires no comma. The phrase “that I would most like to see” is essential to the meaning of the sentence. The sentence will not make sense without this essential phrase.The third example requires two commas, both before and after the nonessential phrase “who is one of my business contacts.” The main message of this sentence—that Pierre will meet this person at the airport—is clear without knowing the additional information about his identity.
18 Sentence Structure: Commas in a Series Place commas in a sentence to divide items in a list.The commas will help the reader to avoid confusion.The comma before the conjunction is generally required, but it can be omitted if there is no possibility of confusion.Key Concept: Commas should be placed between each element within a list. This placement can help the reader to avoid confusion.
19 Sentence Structure: Commas in a Series Consider the difference in the following:Last month, Alex dated Mary Ann Lee and Kim.Last month, Alex dated Mary, Ann, Lee, and Kim.Last month, Alex dated Mary Ann, Lee, and Kim.How many women did Alex date?Activity: These examples illustrate the importance of comma placement within a list. The facilitator may ask students to answer the question “How many women did Alex date?” in accordance with each example—two women in the first, four in the second, and three in the third.
20 Sentence Structure: Commas in a Series Commas should be placed in series of words, phrases, or clauses.Place commas in the following sentences:Martina brushed her hair put on her pajamas and went to bed.She fell asleep and dreamed that she was a princess she kissed a frog and she rescued her prince.Activity: The facilitator may stress to participants that a series includes a list of words, but it can also include a list of phrases or clauses. This exercise allows participants to determine when the commas should be placed in each sentence.
21 Commas with Adjectives Use commas to separate adjectives that provide an equal description of a noun. The test:Can you put “and” between the adjectives?Can they be described in reverse order?If yes, use a comma.Activity: The facilitator may stress to participants that a series includes a list of words, but it can also include a list of phrases or clauses. This exercise allows participants to determine when the commas should be placed in each sentence.
22 A Common Error: The Comma Splice A comma splice is an error in which two independent clauses are joined by a comma.Key Concepts: One of the most prevalent comma errors is the comma splice—the placement of a comma between two independent clauses.
23 To Correct a Comma Splice Insert a conjunction between the two independent clausesStart a new sentenceInsert a semi-colon between the two independent clausesKey Concepts: This slide enumerates several methods for correcting comma splices. The examples listed in the next three slides are corrections of the comma splices in the previous slide.
24 To Correct a Comma Splice How would you correct the following? This semester I am taking calculus physics and economics.Calculus is my best subject, I am certain I will get an A.Although I am very busy, I still find time to have fun.Last weekend my brother visited me and we went to a football game a party and a rock concert.Activity: This slide invites participants to again test their comma skills.The first example requires commas between each element within the list.The second example contains a comma splice. The sentence may be corrected by the addition of a conjunction after the comma, turning the comma splice into a compound sentence. This example may also be corrected by separating the two clauses into two separate sentences, or by changing the comma to a semi-colon.The third example requires a comma after the introductory clause. The facilitator may wish to note that “although” is a dependent clause marker.The fourth example, a compound sentence, requires a comma before the conjunction. Commas are also needed after each element in the list.
25 Where to Go for More Help Purdue University Writing Lab, Heavilon 226 Check our web site:brief questions to OWL Mail:Rationale: As the presentation concludes, the facilitator can remind students that they can come to the Writing Lab for extra help with comma usage.The Writing Lab is located on the West Lafayette Campus in room 226 of Heavilon Hall. The lab is open 9:00am-6:00 pm. OWL, Online Writing Lab, is a reach resource of information. Its address is And finally, you can your questions to OWL Mail at and our tutors will get back to you promptly.Click mouse after the title question.For additional assistance with comma usage, see:Harris, Muriel. Prentice Hall Reference Guide to Grammar and Usage. 4th ed. Upper Saddle River, NJ: Prentice Hall, 2000.
26 The End CONQUERING THE COMMA Purdue OWL staff Brought to you in cooperation with the Purdue Online Writing Lab