Ivy League Mentors Presents
The Complete Guide
to Punctuation
1
Commas (,)
Like all punctuation marks, commas exist to facilitate written communication. Commas customarily
indicate a brief pause; they're not as final as periods. Commas may be small, but don't
underestimate their importance. Consider the following example. It was written by a doctor, which
proves that even highly educated people struggle with comma usage.
“The patient's symptoms include inability to eat diarrhea and headache.”
There are two missing commas in this sentence. Can you locate them? If so, do you see why this
example is so funny and gross?
Most comma errors will not make you laugh, but they might make you cry by costing you valuable
points on your essays in school and on tests like the SAT and ACT. It may take a few reads to
master the rules on this guide, but it will be worth the effort. If you do, you will be able to use
commas correctly and confidently for the rest of your life!
Rule 1: Use commas to separate words and word groups in a simple series of three or more items.
Note that a comma is typically used before the 'and' that precedes the last item on the list, but not
after. Likewise, a comma should likewise precede the term etc.
(X) My estate goes to my husband, son, daughter-in-law and nephew.
(O) Nathan’s website ivyleaguementorsprep.com provides resources on the SAT, the ACT, and more.
Rule 2: Use a comma to separate two adjectives when the order of the adjectives is interchangeable.
Do not use a comma when the order of adjectives is not interchangeable.
(O) Nathan Greenberg is a strong, handsome man.
(X) We stayed at an expensive, summer resort.
Rule 3: Use a comma before a coordinating conjunction when it is used to connect independent
clauses. Note that a comma should never be used to join together two independent clauses without a
coordinating conjunction.
(O) Jason thought carefully, but he still chose the wrong answer.
(O) I was sick, so I didn’t have time to finish my homework.
(X) Jason thought carefully, but still chose the wrong answer.
(X) I was sick, I didn’t have time to finish my homework.
Rule 4: When you start a sentence with a dependent clause, you must use a comma after it.
(O) If you are not sure about this, let me know now.
(X) After Kennedy was assassinated in 1963 he became viewed as a hero.
A comma is unnecessary (and usually omitted) when the sentence starts with an independent clause
followed by a dependent clause.
(X) Let me know now, if you are not sure about this.
(O) Kennedy became viewed as a hero after he was assassinated in 1963.
Rule 5: Use commas to set off nonessential modifiers such as participial phrases, appositive
phrases, and relative clauses, that interrupt the flow of a sentence.
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(O) Hannibal, riding atop a massive elephant, led the charge against Rome.
(X) Jimmy Carter who was president of the United States began his career as a peanut farmer.
(X) The student, exhausted after a hard test collapsed at her desk.
(X) The book, that my teacher recommended is fascinating.
A useful trick is that which clauses are nonessential and require a comma while that clauses are
essential and do not require a comma.
Rule 6: If a detail is required for identification, it is considered essential and should not be
surrounded by commas. Both of the following sentences could be correct, but they have slightly
different meanings.
(O) My sister Becky lives in New York.
Now, see how adding two commas changes that sentence's meaning:
(O) My sister, Becky, lives in New York.
Careful writers and readers understand that the first sentence implies that I have more than one
sister. The commas in the second sentence mean that Becky is my only sister. Let's look at another
example.
(X) Mark Twain's book, Tom Sawyer, is a delight.
Because of the commas, that sentence states that Twain wrote only one book. In fact, he wrote more
than two dozen of them.
A final point is that the indefinite article (a) is a sign that a noun is generic, and therefore, additional
information that is given about it is considered non-essential. Consider the examples below:
(O) Tom Sawyer was written by American author Mark Twain in 1876.
(O) Tom Sawyer was written by the American author Mark Twain in 1876.
(X) Tom Sawyer was written by an American author Mark Twain in 1876.
Rule 7: Use commas to set aside conjunctive adverbs such as however, additionally, indeed,
therefore, and furthermore. If the conjunctive adverb comes at the beginning of a sentence, it should
be followed by a comma. If it comes in the middle of a sentence, it should be surrounded by
commas.
(O) Indeed, some consider him the greatest artist of his era.
(X) Furthermore Buckley was a talented singer.
(X) I'm not tired. I am however, very bored.
Rule 8: Some fixed expressions function as conjunctive adverbs and should also be set aside with
commas. Common examples include in fact, for instance, for example, and in addition.
(X) In fact he is one of the greatest artists of his era.
(X) For example he won the Nobel Prize in 1962.
Rule 9: If a sentence begins with a phrase such as a participial phrase, appositive phrase, or
infinitive phrase, the phrase should be followed by a comma.
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(X) To stay in shape for competition athletes must exercise every day.
(X) Barking insistently Smokey got us to throw his ball for him.
(X) A popular and well respected mayor Bailey was the favorite in the campaign for governor.
Rule 10: If a sentence begins with a long prepositional phrase, it should be followed by a comma.
However, after a short prepositional phrase, the comma is usually omitted. As a general guideline, if
the prepositional phrase is more than two or three words, it is safer to use a comma.
(O) In 1789, the Constitution was ratified.
(O) In 1789 the Constitution was ratified.
(O) During the production of the film, the director nearly quit.
(X) During the production of the film the director nearly quit.
Note that commas are generally not used before prepositional phrases at the end of a sentence.
(X) The director nearly quit, during the production of the film.
Rule 11: Use a comma to separate the day of the month from the year, and put one after the year.
However, no comma is used for just the month and year.
(O) It was in the Sun's June 5, 2003, edition.
(X) It was in a June, 2003 article.
Rule 12: Use a comma to separate a city from its state, and remember to put one after the state,
also. The same rule applies to countries.
(O) I'm from the Boston, Massachusetts, area.
(X) Buenos Aires, Argentina is a beautiful city.
Rule 13: Use commas to introduce or end quotations that interrupt the flow of the sentence. Do not
use commas when the quotation does not interrupt the flow.
(O) He said, "I’m allergic to dogs.”
(X) My friend said that dogs are, “loud, dirty, and obnoxious."
(X) “Though there is much we don’t know about dark energy” asserted the scientist “we are
beginning to realize its important implications for the future of the universe.”
Rule 14: Use a comma to separate contrasting parts of a sentence or to separate a statement from a
question.
(O) I can go, can't I?
(X) That is my money not yours.
Rule 15: Do not use a comma to separate a subject from a verb, even if the subject is a phrase or
clause that would normally require a comma after it.
(X) To start a new business without doing market research in advance, would be foolish.
(X) Extracting the most profit for the least expenditure, is the primary goal of a capitalist.
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Practice 1: Commas
All commas have been omitted from the paragraphs below. Add them wherever appropriate.
1. First recorded in 1835 the disease polio baffled scientific researchers for decades. It was in fact
the most serious public health problem of the mid-20th century and scientists were frantic for a
cure. During the 1940s President Franklin D. Roosevelt was the world’s most recognized polio
victim. In 1938 he founded the organization March of the Dimes to fund the development of a cure.
Before a vaccine was finally discovered by an American scientist Jonas Salk in 1955 more than 80
percent of polio patients received help from the foundation.
2. Jamaica Kincaid born on May 25 1949 is a novelist essayist and gardener. She was born Elaine
Potter Richardson in the town of St. John’s Antigua but came to the United States at the age of 17 to
work as an au pair in Westchester County New York. She eventually won a scholarship to Franconia
College in New Hampshire but returned to New York City to write. In 1985 she published the novel
Annie John a semi-autobiographical story of a young girl growing up in Antigua. In its review of
the novel the New York Times described it as "a clever poignant and profound work."
3. In the mid 1950s most bananas were exported from Guatemala Costa Rica Nicaragua and
Panama. Guatemala a small nation in Central America was a particularly important piece of the vast
empire of banana plantations run by the United Fruit Company. United Fruit Company which was
American-owned paid Guatemala’s government modest sums in exchange for land. With that land
United Fruit planted bananas which it hired local workers to pick. It exercised absolute control over
what workers did how much they were paid and even where they lived. In addition it controlled
transportation constructing the first railway in the country one that was designed to be as useless as
possible for the people of Guatemala and as useful as possible for transporting bananas. The
company’s profits were immense totaling twice the gross domestic product of the entire country of
Guatemala. However while the United Fruit Company invested greatly in its ability to move
bananas little was invested in understanding the biology of bananas themselves.
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Semicolons (;)
Semicolons look like a period stacked on top of a comma. Does that mean you can use it like either
one? Don’t get your hopes up. However, the rules for semicolon usage are actually fairly simple to
master.
Rule 1. Semicolons Connect Related Independent Clauses
You can use a semicolon to join two closely related independent clauses. In this case, a semicolon is
interchangeable with a period. This is by far the most common use of a semicolon that you will
encounter. Keep in mind that the group of words that comes before the semicolon should form a
complete sentence, the group of words that comes after the semicolon should form a complete
sentence, and the two sentences should share a close, logical connection. Consider the examples
that follow:
(O) I ordered a cheeseburger with a large fries for lunch; life’s too short for counting calories.
(X) Although Nathan had a pet turtle; it ran away.
(X) The cheetah is the fastest mammal on earth; reaching speeds of over 60 miles per hour.
(X) Miles Davis was a famous trumpet player; jazz music was developed in the early 20th century in
black neighborhoods in New Orleans, Chicago, and New York.
(X) Hamlet wanted to avenge his father’s death, however, he waited until he had conclusive
evidence.
Rule 2. Delete the Conjunction When You Use a Semicolon
A semicolon isn’t the only thing that can link two independent clauses. Coordinating conjunctions
(remember the FANBOYS) can do that too when they are preceded by a comma. However, you
shouldn’t use a semicolon and a conjunction. Just as a coordinating conjunction would not follow a
period, it should not follow a semicolon.
(O) I saw a magnificent albatross, and it was eating a mouse.
(O) I saw a magnificent albatross; it was eating a mouse.
(X) Scientists believe that dark energy is causing the universe to expand; and it may eventually
cause the universe to tear itself apart, a phenomenon known as the "Big Rip."
(X) Scientists believe that dark energy is causing the universe to expand, it may eventually cause the
universe to tear itself apart, a phenomenon known as the "Big Rip"
Rule 3. Use Semicolons in a Serial List
Although commas are normally used to divide items of a list, you should use semicolons to divide
the items of a list if the items themselves contain internal commas. In these cases, the semicolon
helps readers keep track of the divisions between the items.
(O) My friend plays guitar, piano, and drums; speaks Korean, English, and Chinese; and is
president of her class at school.
(X) I visited London, England, Berlin, Germany, Paris, France, and Lisbon, Portugal.
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Practice 2: Commas & Semicolons
If a sentence or group of sentences has a punctuation error, mark it X and correct the error. If there
is no punctuation error, mark it O.
1.1 Schrodinger's Cat is a thought experiment devised by Austrian physicist Erwin Schrodinger, in
1935; it illustrates what he perceived as a logical flaw, in the Copenhagen interpretation of quantum
mechanics.
1.2 Many people are familiar with Schrodinger's Cat, however, few truly understand the thought
experiment's message which is complicated requiring advanced knowledge of physics.
1.3 Nevertheless, Schrodinger's Cat is often referenced in popular films and television shows; such
as Rick and Morty and Repo Men.
2.1 The novel Things Fall Apart was written by Chinua Achebe; who won the Nobel Prize in
Literature.
2.2 The novel was praised as a critique of colonialism; and it portrays the European conquest of
Nigeria from the perspective of the people, who lived there.
2.3 The protagonist of the novel, a man named Okonkwo, is a fearless warrior, but he is cruel at
times; for instance, he often beats his children and wives.
2.4 After the arrival of Europeans, Okonkwo's village, Umuofia is changed drastically and his
tribe's culture and customs are destroyed; explaining the title Things Fall Apart.
2.5 The novel concludes with Okonkwo's suicide; the life of a once-powerful warrior has ended in
disgrace.
2.6 Some scholars have remarked that Okonkwo resembles an archetypal tragic hero, because he is
a basically good man, who is led to his downfall by a combination of outside forces and his own
mistakes.
3.1 In addition to being the best teacher in the world Nathan is also an accomplished musician.
3.2 First of all, Nathan is a talented jazz bassist, in fact he toured the world as a member of the
Brown University Jazz Band.
3.3 He has performed in jazz clubs in Reykjavik, Iceland, Lisbon, Portugal, Seoul, South Korea,
Buenos Aires, Argentina, and more.
3.4 While Nathan is primarily a jazz bassist, he also plays several other instruments; such as guitar,
piano, drums, and saxophone.
3.5 He also composes music in a number of genres; these genres include rock, hip-hop, folk, and
funk.
3.6 He has written and recorded several albums, with his bands Nathan Mild, Tierpark, July Miles,
and, the Kalavinka Cooperative.
3.7 Unfortunately, Nathan has one major weakness as a musician; his voice.
3.8 Although he has worked hard to improve his voice he is not a natural singer, therefore he will
probably never become very famous as a musician, and should focus on his career as a teacher.
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Colons (:)
Colons are one of the most frequently misused punctuation marks. Keep these simple rules in mind
to ensure that you always use them correctly.
Rule 1: Use a colon to introduce a list, example, explanation, or quotation that elaborates on the
topic or idea mentioned directly before the colon.
(O) We covered many of the fundamentals in our writing class: grammar, punctuation, style, and
voice.
(O) My roommate gave me the things I needed most: companionship and quiet.
(O) Shakespeare said it best: “To thine own self be true.”
(O) Many graduate students discover that there is a dark side to academia: late nights, high stress,
and a crippling addiction to caffeinated beverages.
(O) Life is like a puzzle: half the fun is in trying to work it out.
Rule 2: A colon must be preceded by a complete sentence. The part after the colon may be a
complete sentence, although it does not need to be.
(X) The very best peaches are: those that are grown in the great state of Georgia.
(X) There are many different types of paper, including: college ruled, wide ruled, and plain copy
paper.
(X) My favorite cake is made of: carrots, flour, butter, eggs, and cream cheese icing.
Rule 3: A colon may also be used to express time, in titles, and as part of other specific writing
conventions. Note that these situations are exceptions and the normal rules do not apply, so you
might not see a complete sentence before the colon.
(O) The class has a 2:1 ratio of girls to boys.
(O) The time was 4:52 PM.
(O) My favorite documentary is Everest: The Last Frontier.
(O) Rule 2: A colon must be preceded by a complete sentence.
(O) “When you are on the way to court with your adversary, settle your differences quickly.
Otherwise, your accuser may hand you over to the judge, who will hand you over to an officer, and
you will be thrown into prison.” (Matthew 5:25)
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Practice 3: Commas, Semicolons, and Colons
If a sentence or group of sentences has a punctuation error, mark it X and correct the error. If there
is no punctuation error, mark it O.
1. Benjamin Franklin wrote that, there are only two certainties in life: death and taxes.
2. My brother plays many sports including: soccer, football and tennis.
3. A relationship is like a shark, if it does not move forward constantly it dies.
4. Many are worried that the advent of autonomous vehicles will lead to massive unemployment:
however, autonomous vehicles also have the potential to save lives.
5. Including Alaska and Hawaii; the United States is one of largest countries in the world
comprising nearly 10 million square kilometers.
6. The main ingredients of pizza are: bread, olive oil, cheese, and tomato.
7. Because China censors all references to the Tiananmen Square Massacre in which thousands of
unarmed student protesters were killed; internet users have found a creative method to talk about
the event: a meme involving a rubber duck.
8. Rahsaan Roland Kirk was an American jazz multi-instrumentalist, who played tenor saxophone,
flute, and many other instruments.
9. George Orwell believed that there are four main motives for a writer: sheer egoism, aesthetic
enthusiasm, historical impulse, and, political purpose.
10: There are two primary advantages of nuclear energy; its renewability and its low cost.
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Dashes (—) and Hyphens (–)
Both a dash and a hyphen are little horizontal lines that float in the middle of a line of text. A
hyphen is shorter than a dash, and is used to join together words.
(O) Fast-acting medication can be useful when one has a headache.
(O) Wind-powered generators can be excellent sources of electricity.
(O) The new app was developed by a seventeen-year-old programmer.
A dash is longer than a hyphen and is commonly used to indicate a range or a pause. The first thing
to know when talking about dashes is that they are almost never required by the laws of grammar
and punctuation. Overusing dashes can break up the flow of your writing, making it choppy or even
difficult to follow, so don’t overdo it. With that background information in mind, let’s take a look at
some ways to put dashes to work in your writing.
Rule 1: Use a dash to introduce a list, example, explanation, or detail that elaborates on the topic or
idea mentioned directly before. In this situation, a dash is equivalent to a colon.
(O) We covered many of the fundamentals in our writing class—grammar, punctuation, style, and
voice.
(O) My roommate gave me the things I needed most—companionship and quiet.
(O) Many graduate students discover that there is a dark side to academia—late nights, high stress,
and a crippling addiction to caffeinated beverages.
(O) Life is like a puzzle—half the fun is in trying to work it out.
Rule 2: Use dashes to set aside nonessential information in the middle of a sentence. In this case,
dashes are equivalent to commas, although it should be noted that there is a difference in style.
Dashes draw more attention to the words between them.
(O) The student—exhausted after a hard test—collapsed at her desk.
(O) Everything I saw in my new neighborhood—from the graceful elm trees to the stately brick
buildings—reminded me of a movie.
Note that it is important to be consistent, so even though both commas and dashes can be used in
these cases, they should not be mixed and matched.
(X) Everything I saw in my new neighborhood, from the graceful elm trees to the stately brick
buildings—reminded me of a movie.
(X) Everything I saw in my new neighborhood—from the graceful elm trees to the stately brick
buildings, reminded me of a movie.
Although commas are more common than dashes in these situations, in cases where the
nonessential information includes internal commas, a dash can be preferred.
(O) Even the simplest tasks—washing, dressing, and going to work—were nearly impossible after I
broke my leg.
(X) Even the simplest tasks, washing, dressing, and going to work, were nearly impossible after I
broke my leg.
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Rule 3: Use a dash to break up dialogue. In written dialogue, if a speaker suddenly or abruptly
stops speaking, hesitates in speech, or is cut off by another speaker, a dash can indicate the pause or
interruption.
(O) “I—I don’t know what you’re talking about,” denied the politician.
(O) Daisy began to explain herself, saying, “I was thinking—” “I don’t care what you were
thinking,” Tom interrupted.
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Practice 4: Commas, Semicolons, Colons, and Dashes
If a sentence or group of sentences has a punctuation error, mark it X and correct the error. If there
is no punctuation error, mark it O.
1. George Orwell believed that there are four main motives for a writer—sheer egoism, aesthetic
enthusiasm, historical impulse, and political purpose.
2. The main ingredients of pizza are—bread, olive oil, cheese, and tomato.
3. Freedom of speech—the right to express any opinions without censorship or restraint, is
guaranteed by the Constitution.
4. Even some of the most developed countries in the world, the United States, Italy, Spain, and
England, were devastated by the COVID-19 pandemic.
5. After months of deliberation, the jurors reached a unanimous verdict⁠—guilty.
6. Carcharodon carcharias—more commonly known as the Great White Shark—can weigh over
5,000 pounds, and can swim at speeds of over 25 miles per hour.
7. Mythical creatures—famous examples include the Loch Ness Monster and Bigfoot—have been
the subject of numerous eye-witness accounts but scientists dispute their existence.
8. Though once believed to be ancestors of reptiles, dinosaurs according to most modern
paleontologists were actually more closely related to—birds.
9. "B—but," she stammered shocked by the announcement that she had won the award.
10. Though best known for his contributions to math and physics Einstein was also an
accomplished musician—he was, for example a highly proficient violinist.
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Apostrophes ( ' )
Rule 1: Use an apostrophe followed by an 's' to indicate possession for most nouns.
(O) My cat's favorite food is fish.
(O) Ben Lasman's new book is exceptional.
(X) Apostrophe's are easy to use.
Rule 2: If a noun ends with an 's' because it is plural, use an apostrophe to indicate possession, but
do not follow it with an additional 's.'
(X) My cats's favorite food is fish.
Rule 3: If a noun naturally ends with an 's,' indicate possession with an apostrophe followed by an
's'.
(O) The class's performance has been good.
(X) My brother Chris' apartment is spacious.
Rule 4: Do not use an apostrophe with possessive pronouns.
(X) The cat flicked it's tail.
(X) That book is their's.
Rule 5: Use an apostrophe to indicate a contraction or that letters have been omitted.
(X) Dont feed the animals.
(X) Theyre going to arrive soon.
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Practice 5: Commas, Semicolons, Colons, Dashes, and Apostrophes
If a sentence or group of sentences has a punctuation error, mark it X and correct the error. If there
is no punctuation error, mark it O.
1. I don’t know whether that book is mine or theirs.
2. Executive editors' play one of the most important roles at a newspaper or magazine—they
oversee assistant editors, and have the final input about, which stories are published.
3. Alexander Hamiltons' contributions, as the first treasurer of the United States, were considerable;
he spearheaded the effort to assume state debt, and helped to create a national currency.
4. My teacher, Nathan, is from Boston which is famous for it’s universities, and the Red Sox, the
winner of several recent World Series Championships.
5. My sisters' sense of humor makes them fun companions.
6. Many people like steak; but I, myself, am a pescatarian which means that I dont eat meat, except
fish.
7. Not only musician’s, but also audience members, participated in the concert, it was a memorable
event that received glowing reviews, from the press.
8. While most people have heard of the Great Wall of China few realize that Chinas' "Great Wall"
actually, comprises dozens of smaller walls, that aren't connected.
9. Brexit—Britain's decision to leave the European Union, has been attributed to propaganda spread
by Russian operatives, who wanted to weaken the EU.
10. Marie Curie—a physicist who was awarded the Nobel Prize for her work—died from exposure,
to radiation, that she’d contracted in the process’ of her research.
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