These are main comma rules, but one should note that rules for direct address, clarity, interjections, addresses, dates, and numbers do exist. These rules cover those commas that separate items and those that join items.
Rule 1: Separating Items in a Series
Use a comma to separate items in a list of three or more.
Examples: America’s landscape is composed of deserts, mountains, plains, and forests.
The astronauts’ mission was to land on Mars, take soil samples, and come back safely.
Notice that the items in a series, whether nouns, verbs, or clauses, must remain parallel, meaning that all of the items in that series must be nouns.
Rule 2: Separating Introductory Elements from the Main Clause
Use a comma to separate an introductory word or clause from the independent clause.
Examples: After three years of intense therapy, I was able to write again.
Today, I will call my friend.
Although the terms of the contract were unclear, no one disputed it.
Therefore, you need a comma.
Rule 3: Separating Coordinating Adjectives
Use a comma between coordinating adjectives. You can tell coordinating adjectives by inserting the word “and” between them and switching their order. If they still make sense, they are coordinating and require a comma.
Examples: The dry, boring man was elected to office.
The large brown elephant ramped through the streets. No comma is necessary because “large” is modifying the type of elephant (brown).
Rule 4: Separating Non-Restrictive Elements
Use a comma to set off nonessential clauses and information.
Examples: The people, who do not bathe, are my neighbors.
The people who do not bathe are my neighbors.
In the first case, none of my neighbors bathe. In the second example, only those people identified as those who do not bathe are my neighbors.
Example: Jeff, the surly plumber, just quit smoking.
Rule 5: Joining Independent Clauses with a Conjunction
Use a comma with a conjunction (and, but, or, nor, for, yet, so) when joining independent clauses.
Examples: I was going to the store, and I accidentally went in the wrong direction.
The Chicago Bears looked poised to win yet another division, but after their many injuries, they were left with too many losses to even make the playoffs.
Rule 6: Joining a Direct Quote
Use a comma to introduce a direct quotation after expression verbs (says, states, believes, feels, thinks).
Examples: Banks stated, “let’s play two.” “This is not the end of me,” wrote Sam.
Do not use a comma with an indirect quote; instead, use “that.” Banks stated that he would like to play two games of baseball.
He felt that the rules were too strict.
1. In cases of hurricanes, tornadoes, and cyclones, it is best to hide in the basement, turn off electric equipment and drink bottled water.
In cases, cyclones it equipment, correct as is
2. Ericka and Traci went down to the beach but they forgot their surfboards and were forced to go back home.
Ericka, beach, surfboards, correct as is
3. The people, who live at the end of the block, are noisy.
The people who live at the end of the block are noisy correct as is
4. People, who are also called humans, need food to live.
People who are also called humans need food to live. correct as is
5. Anthony was not in his usual perky self today because of his lack of sleep, his nagging family, and his traffic accident.
Anthony, today, sleep correct as is
6. The nearly indestructible superhero leaped from building to building without damaging the rooftops or his swank fashionable new tights.
nigh, rooftops, swank, correct as is
7. Neither Janice nor Joan knew that their new student lockers would be so near one another.
Janice, knew, new, correct as is
8. While Rupert stated that he needed time to think, Isabella said "Forget you, guy."
stated, think said, correct as is
1. equipment, (item in a list)
2. beach, (two independent clauses joined by a conjunction)
3. The people who live at the end of the block are noisy (just those people)
6. swank, (the adjectives can be switched and separated by "and")
8. said, (direct quotation after an expression verb)
Using apostrophes for contractions should not be done in formal writing. Therefore, these rules for apostrophes cover possession.
Rule 1: Singular Possession To show possessions for singular nouns that do not end in -s, use an -'s.
The dog's bone The man's job Mary's cane
To show possession for singular nouns that end in -s, use -'s or just -' but be consistent. Chris's books or Chris' books
Rule 2: Plural Possession
To show possession for plural words that end in -s, use only an apostrophe.
Two dogs' bones The guys' night out The ladies' apartment
To show possession for plural words that do not end in -s, use an -'s.
The children's dreams The people's champion
Rule 3: Joint Possession To show joint possession (both nouns own the same thing), use -'s with only the last noun.
Example: Jen and Mike's kids will be very tall.
Example: Staci's and John's modes of transportation are very different; Staci takes the train while John drives a new car.
In the first case, the two people share the children. In the second case, each person has his or her own method of travel, so it is not joint possession.
1. Paul's and Susan's dog got out of the yard.
Paul and Susan Paul and Susan's correct
2. The Johnson's moved across the street.
Johnsons' Johnsons correct
3. The cars' tires were stacked near its rear bumper.
car's cars correct
4. Jim and Ryan's pets houses were next door to one another.
Jim's and Ryan's Jim and Ryan correct
1. Paul and Susan's (joint possession; they own they dog)
2. Johnsons (no possession exists)
3. car's (one car as indicated by the "its")
4. Jim's and Ryan's (each owns his own home)
Rule 1: Connecting Independent Clauses Use a semicolon to connect closely related sentences or independent clauses linked with a transition word or phrase.
Example: I went to the store; I was out of milk. The second sentence clarifies the first; therefore, a semicolon is used.
Example: The second sentence clarifies the first; therefore, a semicolon is used.
"Therefore" is a transition word, and the two sentences relate.
Examples of transition words are as follows: Therefore However Nevertheless Thus Finally Likewise Moreover Consequently Instead Still Then Otherwise
Examples of transition phrases are as follows: On the contrary As a result On the other hand In other words For example In fact
Rule 2: Separating items in a list filled with internal punctuation
Example: Dianne, the maid; Theodore, the butler; Anastasia, the nanny; Richard, the cook; and Reginald, the chauffeur are the characters accused of murder in a detective novel.
Because of the commas separating the appositives from their nouns, semicolons are used to keep the sentence clear.
1. I went to the store; and it was crowded.
store; it correct
2. Paul and Erin are engaged therefore, they came together.
engaged; therefore, correct
3. Mr. Smith goes to Washington every year; because in Washington there is great apple picking.
year because correct
4. Sparkles, the dog; Pickles, the cat; Bubbles, the fish; Scaly, the iguana; Rick, the snake; and Percival, the donkey, made the trip with Rebecca to San Diego.
snake, and correct
5. I felt, therefore, that I had a right to the property.
felt; therefore, correct
1. store; it (no need for the conjunction with a semicolon)
2. engaged; therefore, (without the semicolons, the sentence is a run-on)
3. year because (the clause following "because" is dependent)
5. correct (the clause following "that" is dependent)
Rule 1: Introducing a List
Use a colon to introduce a list after an independent clause.
Example: I fear various supernatural creatures: ghosts, goblins, boogie men, and vampires.
Note- Never use a colon after a linking verb (is, are, was, were, feel, seem, become), after a preposition, or after "such as," "like," or "for example."
In each of these cases, no colon is necessary. Simply go on with the sentence without it.
Rule 2: Introducing a Quotation
Use a colon to introduce a quotation after an independent clause.
Example: John Milton had a lofty aim for his Paradise Lost: "To justifie the ways of God."
1. I wished for: candy, a new bicycle, books, a whistle, and a supermodel.
for candy correct
2. To her, the ink blot looked like: an elephant, two runners crossing the finish line, or Elvis having a hot fudge sundae in Central Park.
like an elephant, correct
3. The grocery list contained only a few items, corn, carrots, and Sulfuric acid.
4. In actuality, the party was not fun; it was: boring, overcrowded, overpriced, and smelly.
was boring, correct
5. The following chores are on the "to do" list: shopping, gardening, mopping, washing dishes, doing laundry, and mailing bills.
list shopping correct
1. for candy (a colon cannot interrupt a preposition phrase)
2. like an elephant, (a colon cannot interrupt a dependent clause)
3. items: (a colon introduces a list following an independent clause)
4. was boring, (a colon cannot disrupt a linking verb)
5. correct (the colon introduces a list following the independent clause)