eWorldEditing 고객 지원팀
02-785-4157 (대표전화)
이월드에디팅 카카오톡 채널
신속 무료 추가 교정
USD $1 = KRW 1
Data Souce YAHOO!
교정 금액 계산기
미국 USD
한국 KRW
이월드에디팅 홈페이지는
모바일로도 이용가능합니다
이월드에디팅 소식


Korea’s Number 1 Editing Service for STM (Science, Technology and Medicine) Writers


Proper Comma Usage
-Use a comma when connecting two independent clauses with a conjunction such as but, for, and, or, yet, so, nor. Lack of a comma between two independent clauses separated by a conjunction is likely the most common grammar mistake.


For example: We went swimming, and we watched the sunrise.


-Use a comma to separate a dependent clause at the beginning of a sentence.


For example: After we ate dinner, we played a game.


-Commas are used to separate a string of dependent clauses.


For example: The friends ate dinner, walked the dog, cleaned the yard, and said goodnight.


-When your clauses are independent (they could stand alone as complete sentences), use both a comma and "and" before the final clause:


Betty gets home at 5:30, she changes her clothes, she washes her hair, and she goes to bed around 11:00.


-A non-defining subordinate clause gives extra, unnecessary information about a noun and has no specific function other than additional information. These clauses usually begin with "which" or "who” and should be separated by commas before and after the non-defining subordinate clause or should be followed by a period if they are at the end of a sentence.


For example: The Empire State Building, which was built in 1930, is still New York's tallest building.


The dog is running up and down the street, which is empty of cars.


-Use a comma to separate an appositive from the rest of the sentence; there should be a comma before and after this word or phrase that can be substituted for a name.


An example is “Bob Vance, the president of Vance Refrigeration, married my coworker Phyllis.”


-If you have more than two nouns, separate them with commas. In a list of nouns, you also separate the final two with the word "and" or the word "or."


An example is “The cat, pumpkin, and sign are all orange.”


-Words or phrases used to introduce or interrupt a sentence need a comma. These words and phrases indicate presentation of an important fact or idea and signal a slight interruption in the sentence:


This topic, in my opinion, is not relevant to our discussion.


-Any time you need to offset a clause and provide additional information, be sure to place commas around the clause:


It was the first assay, not the second, that showed the desired results.


-Use a comma after please, a direct address, or to indicate a quote:


"Please," he whispered, "don’t leave me alone."
"Stop," she yelled. "I can’t keep up."
Martin Luther King Jr. said, "The time is always right to do what's right."