Published on
July 1, 2024
by
Eoghan Ryan, MA
Revised on
November 7, 2024
Put a comma before but when it’s used to connect two independent clauses (i.e., two clauses that each contain a subject and a verb).
Example: Commas before but connecting two independent clausesJustinwanted to go to the party, but hewas busy.
Put a comma after but only when it is followed by an interrupter (i.e., a parenthetical expression that qualifies the statement or indicates mood or tone).
Example: Comma after but when using an interrupterBut, having realized his mistake, the doctor apologized.
Published on
July 1, 2024
by
Eoghan Ryan, MA
Revised on
January 13, 2025
A comma splice is a grammatical error that occurs when two independent clauses are incorrectly joined using a comma. A clause is independent if it contains a subject and a verb and expresses a complete thought.
You can correct a comma splice in the following ways:
“Such as” introducing essential identifying information (no comma)
Many European languages, such as Italian and French, are descended from Latin.
Resources such as libraries and online databases are essential to student learning.
The shop sells a number of useful tools, such as hammers, shovels, and rakes.
Jonah enjoys activities such as hiking and swimming.
TipIf you’re unsure whether you need a comma, try removing the “such as” phrase. If the sentence still conveys the same basic meaning, include a comma. If not, don’t include a comma:
“Many European languages are descended from Latin” conveys the same meaning as the original sentence.
“Jonah enjoys activities” is vague and does not express the intended meaning. The “such as” clause is essential, so no comma is needed.
Published on
July 1, 2024
by
Eoghan Ryan, MA
Revised on
September 13, 2024
There should be no comma before “because” when it’s used to introduce a reason that is essential to the meaning of the sentence.
For example, the point of the sentence below is to explain why the project failed.
Example: Because introducing essential informationThe project failed because the team lacked proper communication.
When a comma is added before “because,” the reason is no longer emphasized. Instead, the sentence focuses on the fact the project failed; the reason it failed is less important.
Example: Comma before becauseThe project failed, because the team lacked proper communication.
Published on
June 28, 2024
by
Eoghan Ryan, MA
Revised on
September 12, 2024
You need a comma before the conjunction “so” when it could be replaced with “therefore” (i.e., “for that reason”).
Example: Comma before so meaning “therefore”I was tired, so I went to bed.
I was tired. Therefore, I went to bed.
Example: No comma before so meaning “so that”Tom left early so he could arrive at the office on time.
Tom left early so that he could arrive at the office on time.
When “so” is used as an adverb, pronoun, or other part of speech, commas are generally not needed (e.g., “I hope so,” “he stayed a week or so,” “there’s still so much to do”).
You should put commas before and after “too” when it comes between a verb and its object (i.e., a noun, noun phrase, or pronoun that is affected by the action of a verb).
Example: Comma before too
I hope too that you’ll join us for the party.
I hope, too, that you’ll join us for the party.
When “too” is used at the start of a sentence, it should also be followed by a comma (however, we advise against using “too” in this way).
Published on
June 27, 2024
by
Eoghan Ryan, MA
Revised on
September 30, 2024
The relative pronoun “which” is used to introduce a relative or adjectival clause.
You should put a comma before “which” when it’s used to introduce a nonrestrictive clause—a clause that provides information that is not essential to the meaning of the sentence.
Examples: Comma before “which” introducing a nonrestrictive clauseThe skyscraper, which was built in the 1930s, is being renovated.
She wore a beautiful necklace, which was a gift from her grandmother.
You don’t need a comma before “which” when it’s used to introduce a restrictive clause—a clause that provides essential information, without which the sentence wouldn’t make sense or would mean something else.
Examples: “Which” introducing a restrictive clauseThe cat which lives next door is very friendly.
The book which I’m reading is a bestseller.
TipIf you’re unsure whether a comma is needed before “which,” try omitting the “which” clause from the sentence:
If the basic meaning of the sentence doesn’t change, a comma is required (e.g., “The skyscraper is being renovated”).
If the meaning of the sentence is unclear or less specific, no comma is needed (e.g., “The cat is very friendly”; what cat?).
Published on
June 27, 2024
by
Eoghan Ryan, MA
Revised on
September 13, 2024
Put a comma before “or” when it’s used to connect two independent clauses. A clause is independent if it contains a subject and verb and expresses a complete thought.
Comma before “or” connecting two independent clauses exampleWe might get a late train home, or we might spend the night in the city.
However, when “or” connects two verbs with one subject, it should not be preceded by a comma.
“Or” connecting two verbs with one subject exampleYou can either borrow my bike or walk.
Published on
June 27, 2024
by
Eoghan Ryan, MA
Revised on
September 13, 2024
Put a comma before “and” when it’s used to connect two independent clauses. An independent clause contains both a subject and a verb and can function as a standalone sentence.
Comma before and connecting two independent clause examplesAndycooks dinner, and Danacleans the house.
However, no comma should be used when “and” connects two verbs with the same subject. In the following example, the subject, Peter, performs both actions (working and sleeping).
And connecting two verbs with one subject examplePeterworks at night and sleeps during the day.