Achievable Praxis Core: Writing (5723)

2. Language and research skills

2.2. Punctuation

2.2.2. Commas

Our Praxis Core: Writing course is currently in development and is a work-in-progress.

Commas + FANBOYS and lists

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Commas are confusing because they have multiple uses. Many students make mistakes on comma questions because they jump to conclusions as soon as they see one or two instead of taking the time to read the whole sentence and understand its structure.

For example:

After taking out the trash, Mira decided that she wasn’t tired after all, so she weeded the herb garden, did the laundry, and baked six loaves of bread.

The above sentence contains four commas. The first one marks the end of the introductory phrase, After taking out the trash. The second comma is paired with the FANBOYS so, and it connects the sentence’s two main clauses:

Mira decided that she wasn’t tired after all, so she weeded the herb garden, did the laundry, and baked six loaves of bread.

The second main clause contains a list:

She weeded the herb garden, did the laundry, and baked six loaves of bread.

The third and fourth commas divide the items on the list.

Even good readers can be confused by long, multi-comma sentences. However, if you memorize the comma rules and read test questions carefully, you can ace the comma questions on the Writing test.

Comma + FANBOYS

You already know two ways to separate two main clauses:

a period
a semicolon

The third way is to place a comma before one of the FANBOYS, an easily memorized group of seven conjunctions:

Definitions

FANBOYS: For, And, Nor, But, Or, Yet, So

In each case, the comma + FANBOYS combination connects two main clauses, which means that each clause could be a sentence on its own.

Watch out for comma splices: a comma by itself can’t join two main clauses. Fix a splice by adding one of the seven FANBOYS words right after the comma, or by replacing the comma with a semicolon or a period.

INCORRECT: Susan’s coffee was hot, she waited to sip it.

CORRECT: Susan’s coffee was hot, so she waited to sip it.

ALSO CORRECT: Susan’s coffee was hot; she waited to sip it.

FANBOYS word	Meaning	Example
For	means “because” (but unlike because, for can follow a comma)	Rachel hurried to get ready, for she didn’t want to be late for the play.
And	adds a related idea	Ismail graduated at the top of his class, and he was instantly hired by a top firm.
Nor	adds a second negative idea	Alfie didn’t want to go to the playground, nor did he want to go in the pool.
But	introduces a contrast	It’s cooling down outside, but I don’t think we should turn the air conditioning off yet.
Or	presents a choice	I can go for a run, or I can study for that exam.
Yet	means “but,” often with surprise	Stanley studied hard, yet he scored 13% on the test.
So	expresses cause and effect	Kira was a vegan, so she refused Timmy’s offer of a ham and egg sandwich.

Nor requires inversion

Nor flips the subject and verb order in the clause that follows it.

INCORRECT: Alfie didn’t want to go to the playground, nor he did want to go in the pool.

CORRECT: Alfie didn’t want to go to the playground, nor did he want to go in the pool.

And and compound predicates

Watch out when the second part of an and sentence drops its subject. Without a repeated subject, the part after and isn’t a second main clause—it’s a compound predicate, a second verb attached to the same subject. Since there’s only one clause, no comma belongs before and.

INCORRECT: Ismail graduated at the top of his class, and was instantly hired by a top firm.

CORRECT: Ismail graduated at the top of his class and was instantly hired by a top firm.

Practice question

Susan’s coffee was hot so she waited to sip it until she had finished her sandwich.

Choose the correct answer:

a. Susan’s coffee was hot so she waited to sip it until she had finished her sandwich.
b. Susan’s coffee was hot, so she waited to sip it, until she had finished her sandwich.
c. Susan’s coffee was hot, so she waited, to sip it until she had finished her sandwich.
d. Susan’s coffee was hot, so she waited to sip it until she had finished her sandwich.
e. Susan’s coffee was hot; so she waited to sip it until she had finished her sandwich.

Correct answer:

(spoiler)

The correct answer is d. Susan’s coffee was hot, so she waited to sip it until she had finished her sandwich.

a. repeats the original wording, which is incorrect because there is no comma before so, and so is joining two main clauses.

b. is incorrect because there should not be a comma before until.

c. is incorrect because the comma breaks up the verb phrase waited to sip.

d. is correct because comma + so correctly joins two main clauses.

e. is incorrect because a semicolon already joins the two main clauses by itself. Pair so with a comma, not a semicolon.

Practice question

Charlie missed class because he got clobbered on the head by a basketball during practice last night, and he still has a terrible headache.

Choose the correct answer:

a. Charlie missed class because he got clobbered on the head by a basketball during practice last night, and he still has a terrible headache.
b. Charlie missed class because he got clobbered on the head by a basketball during practice last night and he still has a terrible headache.
c. Charlie missed class, because he got clobbered on the head by a basketball during practice last night, and he still has a terrible headache.
d. Charlie missed class because he got clobbered on the head, by a basketball during practice last night and he still has a terrible headache.
e. Charlie missed class because he got clobbered, on the head by a basketball during practice last night, and he still has a terrible headache.

Correct answer:

(spoiler)

The correct answer is a, which repeats the original wording.

a. is correct. There are no unnecessary commas, and the two main clauses are correctly connected with comma + and.

b. is incorrect because the comma before and is missing, and and joins two main clauses.

c. is incorrect because there should not be a comma before because.

d. is incorrect because the comma before by incorrectly breaks up the phrase.

e. is incorrect because the comma after clobbered wrongly separates the verb from the phrase that completes it.

Commas in lists

Commas separate items in a list whenever the list contains three or more items. Add and (or or) before the final item.

Nelson liked baseball, hockey, and basketball.

The comma before the final item is called the Oxford comma. It’s technically optional, but test writers consistently use it, so choose the answer that includes it when the other choices are equally correct.

The lunch menu for the week consisted of tacos, pizza, hamburgers, chicken nuggets, and tuna sandwiches.

Practice question

To earn money for a new gaming system, Aaron mowed lawns, walked dogs, and babysat his neighbor’s twin toddlers.

Choose the correct answer:

a. To earn money for a new gaming system, Aaron mowed lawns, walked dogs, and babysat his neighbor’s twin toddlers.
b. To earn money for a new gaming system, Aaron mowed lawns walked dogs, and babysat his neighbor’s twin toddlers.
c. To earn money for a new gaming system, Aaron mowed lawns, walked dogs and babysat his neighbor’s twin toddlers.
d. To earn money for a new gaming system, Aaron mowed lawns, walked dogs, and babysat his neighbor’s, twin toddlers.
e. To earn money for a new gaming system Aaron mowed lawns walked dogs and babysat his neighbor’s twin toddlers.

Correct answer:

(spoiler)

The correct answer is a, which repeats the original wording.

a. is correct. Aaron’s three actions are correctly separated with commas.

b. is incorrect because the comma after lawns is missing.

c. leaves out the serial comma after dogs. Choice a is the more standard form tests expect.

d. is incorrect because there should not be a comma after neighbor’s.

e. is incorrect because the sentence is missing the commas needed for both the introductory phrase and the list.

Comma + FANBOYS (joining main clauses)

Three ways to join two main clauses: period, semicolon, or comma + FANBOYS (For, And, Nor, But, Or, Yet, So)
Comma splice error: a comma alone cannot join two main clauses — fix by adding a FANBOYS word, or replacing comma with semicolon/period
Each FANBOYS word has a specific meaning (e.g., for = because, so = cause/effect, yet = contrast/surprise, nor = adds second negative)

Special FANBOYS rules

Nor requires subject-verb inversion in the clause that follows it (e.g., “nor did he want…”)
And + compound predicate: if the second part of the sentence drops its subject, it’s not a second main clause but a compound predicate (same subject, second verb) — no comma needed before and in this case

Commas in lists

Use commas to separate 3+ items in a series, with and/or before the final item
The comma before the final item is the Oxford comma — technically optional, but standard on tests, so prefer answers that include it
Example pattern: item1, item2, and item3

Next | 2.2.2.2 Commas and subordinate clauses

Commas + FANBOYS and lists

For example:

After taking out the trash, Mira decided that she wasn’t tired after all, so she weeded the herb garden, did the laundry, and baked six loaves of bread.

Mira decided that she wasn’t tired after all, so she weeded the herb garden, did the laundry, and baked six loaves of bread.

The second main clause contains a list:

She weeded the herb garden, did the laundry, and baked six loaves of bread.

The third and fourth commas divide the items on the list.

Even good readers can be confused by long, multi-comma sentences. However, if you memorize the comma rules and read test questions carefully, you can ace the comma questions on the Writing test.

Comma + FANBOYS

You already know two ways to separate two main clauses:

a period
a semicolon

The third way is to place a comma before one of the FANBOYS, an easily memorized group of seven conjunctions:

Definitions

FANBOYS: For, And, Nor, But, Or, Yet, So

In each case, the comma + FANBOYS combination connects two main clauses, which means that each clause could be a sentence on its own.

INCORRECT: Susan’s coffee was hot, she waited to sip it.

CORRECT: Susan’s coffee was hot, so she waited to sip it.

ALSO CORRECT: Susan’s coffee was hot; she waited to sip it.

FANBOYS word	Meaning	Example
For	means “because” (but unlike because, for can follow a comma)	Rachel hurried to get ready, for she didn’t want to be late for the play.
And	adds a related idea	Ismail graduated at the top of his class, and he was instantly hired by a top firm.
Nor	adds a second negative idea	Alfie didn’t want to go to the playground, nor did he want to go in the pool.
But	introduces a contrast	It’s cooling down outside, but I don’t think we should turn the air conditioning off yet.
Or	presents a choice	I can go for a run, or I can study for that exam.
Yet	means “but,” often with surprise	Stanley studied hard, yet he scored 13% on the test.
So	expresses cause and effect	Kira was a vegan, so she refused Timmy’s offer of a ham and egg sandwich.

Nor requires inversion

Nor flips the subject and verb order in the clause that follows it.

INCORRECT: Alfie didn’t want to go to the playground, nor he did want to go in the pool.

CORRECT: Alfie didn’t want to go to the playground, nor did he want to go in the pool.

And and compound predicates

INCORRECT: Ismail graduated at the top of his class, and was instantly hired by a top firm.

CORRECT: Ismail graduated at the top of his class and was instantly hired by a top firm.

Practice question

Susan’s coffee was hot so she waited to sip it until she had finished her sandwich.

Choose the correct answer:

a. Susan’s coffee was hot so she waited to sip it until she had finished her sandwich.
b. Susan’s coffee was hot, so she waited to sip it, until she had finished her sandwich.
c. Susan’s coffee was hot, so she waited, to sip it until she had finished her sandwich.
d. Susan’s coffee was hot, so she waited to sip it until she had finished her sandwich.
e. Susan’s coffee was hot; so she waited to sip it until she had finished her sandwich.

Correct answer:

(spoiler)

The correct answer is d. Susan’s coffee was hot, so she waited to sip it until she had finished her sandwich.

a. repeats the original wording, which is incorrect because there is no comma before so, and so is joining two main clauses.

b. is incorrect because there should not be a comma before until.

c. is incorrect because the comma breaks up the verb phrase waited to sip.

d. is correct because comma + so correctly joins two main clauses.

e. is incorrect because a semicolon already joins the two main clauses by itself. Pair so with a comma, not a semicolon.

Practice question

Charlie missed class because he got clobbered on the head by a basketball during practice last night, and he still has a terrible headache.

Choose the correct answer:

a. Charlie missed class because he got clobbered on the head by a basketball during practice last night, and he still has a terrible headache.
b. Charlie missed class because he got clobbered on the head by a basketball during practice last night and he still has a terrible headache.
c. Charlie missed class, because he got clobbered on the head by a basketball during practice last night, and he still has a terrible headache.
d. Charlie missed class because he got clobbered on the head, by a basketball during practice last night and he still has a terrible headache.
e. Charlie missed class because he got clobbered, on the head by a basketball during practice last night, and he still has a terrible headache.

Correct answer:

(spoiler)

The correct answer is a, which repeats the original wording.

a. is correct. There are no unnecessary commas, and the two main clauses are correctly connected with comma + and.

b. is incorrect because the comma before and is missing, and and joins two main clauses.

c. is incorrect because there should not be a comma before because.

d. is incorrect because the comma before by incorrectly breaks up the phrase.

e. is incorrect because the comma after clobbered wrongly separates the verb from the phrase that completes it.

Commas in lists

Commas separate items in a list whenever the list contains three or more items. Add and (or or) before the final item.

Nelson liked baseball, hockey, and basketball.

The lunch menu for the week consisted of tacos, pizza, hamburgers, chicken nuggets, and tuna sandwiches.

Practice question

To earn money for a new gaming system, Aaron mowed lawns, walked dogs, and babysat his neighbor’s twin toddlers.

Choose the correct answer:

a. To earn money for a new gaming system, Aaron mowed lawns, walked dogs, and babysat his neighbor’s twin toddlers.
b. To earn money for a new gaming system, Aaron mowed lawns walked dogs, and babysat his neighbor’s twin toddlers.
c. To earn money for a new gaming system, Aaron mowed lawns, walked dogs and babysat his neighbor’s twin toddlers.
d. To earn money for a new gaming system, Aaron mowed lawns, walked dogs, and babysat his neighbor’s, twin toddlers.
e. To earn money for a new gaming system Aaron mowed lawns walked dogs and babysat his neighbor’s twin toddlers.

Correct answer:

(spoiler)

The correct answer is a, which repeats the original wording.

a. is correct. Aaron’s three actions are correctly separated with commas.

b. is incorrect because the comma after lawns is missing.

c. leaves out the serial comma after dogs. Choice a is the more standard form tests expect.

d. is incorrect because there should not be a comma after neighbor’s.

e. is incorrect because the sentence is missing the commas needed for both the introductory phrase and the list.

Key points

Comma + FANBOYS (joining main clauses)

Three ways to join two main clauses: period, semicolon, or comma + FANBOYS (For, And, Nor, But, Or, Yet, So)
Comma splice error: a comma alone cannot join two main clauses — fix by adding a FANBOYS word, or replacing comma with semicolon/period
Each FANBOYS word has a specific meaning (e.g., for = because, so = cause/effect, yet = contrast/surprise, nor = adds second negative)

Special FANBOYS rules

Nor requires subject-verb inversion in the clause that follows it (e.g., “nor did he want…”)
And + compound predicate: if the second part of the sentence drops its subject, it’s not a second main clause but a compound predicate (same subject, second verb) — no comma needed before and in this case

Commas in lists

Use commas to separate 3+ items in a series, with and/or before the final item
The comma before the final item is the Oxford comma — technically optional, but standard on tests, so prefer answers that include it
Example pattern: item1, item2, and item3

For example:

After taking out the trash, Mira decided that she wasn’t tired after all, so she weeded the herb garden, did the laundry, and baked six loaves of bread.

Mira decided that she wasn’t tired after all, so she weeded the herb garden, did the laundry, and baked six loaves of bread.

The second main clause contains a list:

She weeded the herb garden, did the laundry, and baked six loaves of bread.

The third and fourth commas divide the items on the list.

Even good readers can be confused by long, multi-comma sentences. However, if you memorize the comma rules and read test questions carefully, you can ace the comma questions on the Writing test.

Comma + FANBOYS

You already know two ways to separate two main clauses:

a period
a semicolon

The third way is to place a comma before one of the FANBOYS, an easily memorized group of seven conjunctions:

Definitions

FANBOYS: For, And, Nor, But, Or, Yet, So

In each case, the comma + FANBOYS combination connects two main clauses, which means that each clause could be a sentence on its own.

INCORRECT: Susan’s coffee was hot, she waited to sip it.

CORRECT: Susan’s coffee was hot, so she waited to sip it.

ALSO CORRECT: Susan’s coffee was hot; she waited to sip it.

FANBOYS word	Meaning	Example
For	means “because” (but unlike because, for can follow a comma)	Rachel hurried to get ready, for she didn’t want to be late for the play.
And	adds a related idea	Ismail graduated at the top of his class, and he was instantly hired by a top firm.
Nor	adds a second negative idea	Alfie didn’t want to go to the playground, nor did he want to go in the pool.
But	introduces a contrast	It’s cooling down outside, but I don’t think we should turn the air conditioning off yet.
Or	presents a choice	I can go for a run, or I can study for that exam.
Yet	means “but,” often with surprise	Stanley studied hard, yet he scored 13% on the test.
So	expresses cause and effect	Kira was a vegan, so she refused Timmy’s offer of a ham and egg sandwich.

Nor requires inversion

Nor flips the subject and verb order in the clause that follows it.

INCORRECT: Alfie didn’t want to go to the playground, nor he did want to go in the pool.

CORRECT: Alfie didn’t want to go to the playground, nor did he want to go in the pool.

And and compound predicates

INCORRECT: Ismail graduated at the top of his class, and was instantly hired by a top firm.

CORRECT: Ismail graduated at the top of his class and was instantly hired by a top firm.

Practice question

Susan’s coffee was hot so she waited to sip it until she had finished her sandwich.

Choose the correct answer:

a. Susan’s coffee was hot so she waited to sip it until she had finished her sandwich.
b. Susan’s coffee was hot, so she waited to sip it, until she had finished her sandwich.
c. Susan’s coffee was hot, so she waited, to sip it until she had finished her sandwich.
d. Susan’s coffee was hot, so she waited to sip it until she had finished her sandwich.
e. Susan’s coffee was hot; so she waited to sip it until she had finished her sandwich.

Correct answer:

(spoiler)

The correct answer is d. Susan’s coffee was hot, so she waited to sip it until she had finished her sandwich.

a. repeats the original wording, which is incorrect because there is no comma before so, and so is joining two main clauses.

b. is incorrect because there should not be a comma before until.

c. is incorrect because the comma breaks up the verb phrase waited to sip.

d. is correct because comma + so correctly joins two main clauses.

e. is incorrect because a semicolon already joins the two main clauses by itself. Pair so with a comma, not a semicolon.

Practice question

Charlie missed class because he got clobbered on the head by a basketball during practice last night, and he still has a terrible headache.

Choose the correct answer:

a. Charlie missed class because he got clobbered on the head by a basketball during practice last night, and he still has a terrible headache.
b. Charlie missed class because he got clobbered on the head by a basketball during practice last night and he still has a terrible headache.
c. Charlie missed class, because he got clobbered on the head by a basketball during practice last night, and he still has a terrible headache.
d. Charlie missed class because he got clobbered on the head, by a basketball during practice last night and he still has a terrible headache.
e. Charlie missed class because he got clobbered, on the head by a basketball during practice last night, and he still has a terrible headache.

Correct answer:

(spoiler)

The correct answer is a, which repeats the original wording.

a. is correct. There are no unnecessary commas, and the two main clauses are correctly connected with comma + and.

b. is incorrect because the comma before and is missing, and and joins two main clauses.

c. is incorrect because there should not be a comma before because.

d. is incorrect because the comma before by incorrectly breaks up the phrase.

e. is incorrect because the comma after clobbered wrongly separates the verb from the phrase that completes it.

Commas in lists

Commas separate items in a list whenever the list contains three or more items. Add and (or or) before the final item.

Nelson liked baseball, hockey, and basketball.

The lunch menu for the week consisted of tacos, pizza, hamburgers, chicken nuggets, and tuna sandwiches.

Practice question

To earn money for a new gaming system, Aaron mowed lawns, walked dogs, and babysat his neighbor’s twin toddlers.

Choose the correct answer:

a. To earn money for a new gaming system, Aaron mowed lawns, walked dogs, and babysat his neighbor’s twin toddlers.
b. To earn money for a new gaming system, Aaron mowed lawns walked dogs, and babysat his neighbor’s twin toddlers.
c. To earn money for a new gaming system, Aaron mowed lawns, walked dogs and babysat his neighbor’s twin toddlers.
d. To earn money for a new gaming system, Aaron mowed lawns, walked dogs, and babysat his neighbor’s, twin toddlers.
e. To earn money for a new gaming system Aaron mowed lawns walked dogs and babysat his neighbor’s twin toddlers.

Correct answer:

(spoiler)

The correct answer is a, which repeats the original wording.

a. is correct. Aaron’s three actions are correctly separated with commas.

b. is incorrect because the comma after lawns is missing.

c. leaves out the serial comma after dogs. Choice a is the more standard form tests expect.

d. is incorrect because there should not be a comma after neighbor’s.

e. is incorrect because the sentence is missing the commas needed for both the introductory phrase and the list.