The Importance of Commas
Commas play a significant role in sentence structure and are essential for conveying meaning and clarity in written language. Understanding when to use commas is crucial for effective communication and ensuring that your sentences are grammatically correct.
The Role of Commas in Sentence Structure
Commas serve several purposes in sentence structure. They help to indicate pauses, separate items in a list, and provide clarity in complex sentences. Commas can also be used to set off introductory phrases, nonessential information, and direct quotations.
By using commas appropriately, you can guide readers through your writing, helping them understand the intended meaning and emphasizing key elements of your sentences.
When to Use Commas
Knowing when to use commas can be challenging, as there are various rules and guidelines to consider. Here are some common situations in which commas are typically used:
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Separating items in a list: Commas are used to separate three or more items in a list. For example: “She bought apples, oranges, and bananas.”
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Setting off introductory phrases: Commas are used after introductory phrases that come at the beginning of a sentence. For example: “In the morning, I go for a run.”
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Separating coordinate adjectives: When two or more adjectives independently modify a noun, a comma is used to separate them. For example: “She wore a soft, cozy sweater.”
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Setting off nonessential information: Commas are used to separate nonessential information, such as additional details or clarifications, from the main sentence. For example: “The book, which was written by my favorite author, is a bestseller.”
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Separating clauses in a compound sentence: Commas are used to separate two or more independent clauses joined by coordinating conjunctions such as “and,” “but,” or “or.” For example: “She went to the store, and he stayed at home.”
These are just a few examples of when commas are commonly used. It’s important to familiarize yourself with the various comma rules to ensure accurate and effective use in your writing. For more insights on comma usage in specific contexts, consider exploring our articles on starting a sentence with “whereas” and using a comma after “here”.
Understanding the role of commas and when to use them is fundamental for mastering the art of clear and concise writing. By using commas correctly, you enhance the readability and comprehension of your sentences, making your writing more impactful and professional.
Understanding “That Is”
In order to master the usage of commas before and after “that is,” it is important to understand the function of this phrase in sentences and how it can be used for clarification.
The Function of “That Is” in Sentences
“That is” is a phrase used to provide further explanation or clarification about a previous statement or to introduce a specific example or explanation. It acts as a signal to the reader that additional information is about to be provided.
For example:
- She loves all kinds of music, from classical to jazz. That is, she enjoys a wide range of musical genres.
- Our team completed the project successfully. That is, we met all the deadlines and achieved the desired outcomes.
In these examples, “that is” is used to add more information or to rephrase the previous statement in a clearer way.
Using “That Is” for Clarification
One of the main purposes of using “that is” in a sentence is to provide clarification. It allows you to add more specific details or rephrase a statement to ensure that the reader understands your intended meaning.
For instance:
- The painting is an original work of art. That is, it was created by a renowned artist and is not a replica.
- The conference will be held at the Grand Hotel. That is, the venue has been changed from the previous announcement.
In these examples, “that is” is used to provide additional information that clarifies the initial statement. It helps to avoid ambiguity and ensures that the reader has a clear understanding of the intended message.
Understanding the function of “that is” in sentences is crucial when considering the appropriate use of commas before and after this phrase. In the following sections, we will explore the cases that require a comma before “that is” and the cases that require a comma after “that is.”
Using Commas Before “That Is”
When it comes to the phrase “that is,” the use of commas can sometimes be necessary to enhance clarity and improve sentence structure. Let’s explore the cases that require a comma before “that is” and provide examples of proper usage.
Cases Requiring a Comma Before “That Is”
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Introductory Phrases or Clauses: When “that is” is used to introduce a phrase or clause at the beginning of a sentence, a comma should be placed after it. This helps to separate the introductory element from the main clause.
- Example: “That is, I believe we should proceed with caution.”
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Parenthetical Statements: If “that is” is used within parentheses or as an interrupting element within a sentence, it should be set off by commas. This ensures that the main clause remains clear and unobstructed.
- Example: **”We have considered all the options, including, **that is, the possibility of starting from scratch.”
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Appositive Phrases: An appositive phrase provides additional information about a noun or pronoun in a sentence. When “that is” is used as an appositive phrase, it should be set off by commas.
- Example: **”The painting, a masterpiece in its own right, was created by a renowned artist, **that is, Van Gogh.”
Examples of Proper Usage
To further illustrate the proper usage of commas before “that is,” let’s explore some additional examples:
- Introductory Phrase:
- Incorrect: “That is we need to address the issue immediately.”
- Correct: “That is, we need to address the issue immediately.”
- Parenthetical Statement:
- Incorrect: “We have, that is no doubt, made progress.”
- Correct: “We have, that is, no doubt, made progress.”
- Appositive Phrase:
- Incorrect: “The dog a loyal companion that is, always stays by my side.”
- Correct: “The dog, a loyal companion, that is, always stays by my side.”
By using commas before “that is” in the appropriate cases, you can ensure that your sentences are clear, well-structured, and effectively convey your intended meaning.
Using Commas After “That Is”
In some cases, it is necessary to use a comma after the phrase “that is” to ensure clarity and proper sentence structure. Let’s explore the situations where a comma is required after “that is” and provide examples of proper usage.
Cases Requiring a Comma After “That Is”
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Appositive Phrases: When “that is” is followed by an appositive phrase, which provides additional information about the preceding noun, a comma should be used after “that is.” This helps to separate the appositive phrase from the rest of the sentence and improves readability.
Example:
- The president of the company, that is, the person in charge of all operations, made an important announcement.
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Introducing Examples or Explanations: When “that is” introduces examples or explanations of the preceding statement, a comma should be used to signal the transition. This helps to distinguish the additional information from the main clause.
Example:
- She loves outdoor activities, that is, hiking, swimming, and cycling.
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Clarifying a Previous Statement: When “that is” is used to clarify or rephrase a previous statement, a comma is typically used after “that is.” This helps to indicate the separation between the restatement and the original statement.
Example:
- The concert was postponed until next week, that is, it will now take place on Friday instead of Thursday.
Examples of Proper Usage
To further illustrate the proper usage of commas after “that is,” consider the following examples:
Example | Correct Usage |
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I have a favorite color, that is, blue. | Commas are used to set off the appositive phrase “that is” from the main clause. |
They enjoy various genres of music, that is, classical, jazz, and rock. | A comma is used to introduce examples of the genres of music they enjoy. |
The store is offering a discount, that is, 20% off all items. | A comma is used to clarify the discount being offered. |
By using commas after “that is” in these specific cases, you can ensure that your writing is clear and effectively conveys the intended meaning. Remember to always consider the context and purpose of your sentence to determine whether a comma is needed after “that is.”
Common Mistakes to Avoid
When it comes to using commas with the phrase “that is,” there are some common mistakes that writers should avoid. Incorrect placement of commas can lead to confusion and disrupt the flow of a sentence. Here are some key mistakes to watch out for, along with tips for correct usage.
Incorrect Placement of Commas with “That Is”
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No comma before “that is” when it introduces a restrictive clause: One common mistake is failing to use a comma before “that is” when it introduces a restrictive clause. A restrictive clause provides essential information that is necessary to identify the noun it modifies. For example:
Incorrect: The book that is on the table is mine.
Correct: The book, that is on the table, is mine.
In the correct version, the comma before “that is” sets off the clause and helps clarify that the speaker is referring to a specific book on the table.
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Unnecessary comma after “that is” when it introduces a non-restrictive clause: Another mistake is using a comma after “that is” when it introduces a non-restrictive clause. A non-restrictive clause provides additional information that is not essential for identifying the noun it modifies. For example:
Incorrect: The book, that is, on the table, is mine.
Correct: The book that is on the table is mine.
In the correct version, the absence of a comma after “that is” indicates that the clause is non-restrictive and the information about the book being on the table is not necessary for identifying it as the speaker’s.
Tips for Correct Usage
To ensure proper usage of commas with “that is,” consider the following tips:
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Determine if the clause is restrictive or non-restrictive: Identify whether the information provided by the clause is necessary for identifying the noun it modifies (restrictive) or if it provides additional, non-essential information (non-restrictive).
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Use a comma before “that is” for restrictive clauses: If the clause is restrictive, meaning it is necessary for identifying the noun, use a comma before “that is” to set off the clause.
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Avoid a comma after “that is” for non-restrictive clauses: If the clause is non-restrictive, meaning it provides additional information but is not necessary for identifying the noun, do not use a comma after “that is.”
By understanding these common mistakes and following the tips for correct usage, you can effectively use commas with the phrase “that is” to enhance the clarity and readability of your writing.
Practice Makes Perfect
To solidify your understanding of using commas before and after “that is,” here are some exercises that will help you practice and reinforce the rules.
Exercises to Test Your Understanding
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Read the following sentences and determine whether a comma should be placed before or after “that is.” Write “B” for before and “A” for after.
a) She wanted to go to the park(,) that is her favorite place to relax.
b) The book(,) that is a classic(,) was written in the 19th century.
c) I need to buy some groceries(,) that is, milk, eggs, and bread.
d) He is an expert in his field(,) that is why he is highly sought after.
e) The concert(,) that is scheduled for tomorrow(,) was canceled due to bad weather.
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Rewrite the following sentences by correctly placing the commas before or after “that is.”
a) I have a dog that is playful.
b) The movie that is coming out next week is highly anticipated.
c) She has a collection of books that is extensive.
d) We went to the beach that is our favorite spot.
e) The cake that is chocolate is my favorite.
Further Resources for Learning
To further enhance your understanding of comma usage and grammar principles, consider exploring the following resources:
- Can You Start a Sentence with “Whereas”?
- Comma After “Here”
- Professional Ways to Say “Okay”
- Category Synonyms
- Polite Ways to Ask for a Meeting Place and Time
- Formal Synonyms for “I Would Like to Know”
- Lady’s Possessive
- Guy’s Possessive
- Comma Before Ampersand
By practicing these exercises and exploring additional resources, you will gain confidence in using commas correctly with “that is” and expand your overall grammar skills.