When to use a comma?
A. Use commas to avoid confusion.
(1a) I intend to share my vacation home with my parents, Mary and Joe.
=> This means: I intend to share my vacation home with my parents. My parents’ names are Mary and Joe. I will be sharing my vacation home with both of them.
(1b) I intend to share my vacation home with my parents, Mary, and Joe.
=> This means: I intend to share my vacation home with my parents, with Mary and with Joe. So I will be sharing my vacation home with four people.
(2a) I cannot stand a hypocrite like you. I hate politics.
=> This means: You are a hypocrite. I cannot stand you.
(2b) I cannot stand a hypocrite; like you, I hate politics.
=> This means: I am like you. I cannot stand a hypocrite
(3) I like eating meat and vegetable, and fruit is her favorite.
=> This means: I like eating meat and vegetable. She likes eating fruit the most. I did not mention if I like eating fruit or not.
(4) To Cindy, Brook is nothing but a trouble.
=> This means: Brook is a trouble in the eyes of Cindy.
(5) Outside, the garden was cluttered with faded flowers.
=> Without the comma, it will mean “outside the garden” instead of “outside”, and the grammar will be inaccurate.
(不用逗號正確語法: Outside the garden were clusters of faded flowers.)
See the difference!
** Without comma, they will be treated as a unit.
(6a) For dinner, I want meatloaf, banana, macaroni, and cheese.
=> This means: I want four items prepared separately. I want cheese in addition to macaroni.
(6b) For dinner, I want meatloaf, banana, macaroni and cheese.
=> This means: macaroni and cheese is one item.
B. Use commas to separate independent clauses when they are joined by any of these seven coordinating conjunctions: and, but, for, or, nor, so, yet.
Ø I like taking my vacation in the winter, and she likes taking hers in the summer.
Ø I like going shopping, but I cannot stand the crowd.
Ø I have finished my lunch, yet I still feel hungry.
Ø I don’t agree with the result of his experiment, so I decide to do it myself.
Ø I decided to run for city mayor, for I believe that I have much to offer to the city.
Ø Mary cannot decide whether she should stay here with her family, or fly to London to join her boyfriend.
Ø Hardly can I determine which proposal to follow, nor am I capable of coming up with a more innovative one.
Ø I like eating meat and vegetable, while she likes to eat fruit. (while = but)
C. Use commas to separate three or more words, phrases, or clauses written in a series.
Ø Kevin and I started our 2 week vacation to Mount Rushmore, Rocky Mountains, and Grand Canyon.
Ø As an exchange for a trip to Legoland, our kids agreed to listen to our command, (to) show their best behaviors, and (to) do their own chores.
Ø Mary, who had a strong motive, who was prosecuted for murder, and who had been on suicide watch, was recently found not guilty.
Ø I will help you if you stop smoking, if you exercise every day, and if you promise not to drink anymore.
Ø Joanne has a most kind, sensitive, and untamed heart.
Ø Timmy kicked Jack in the butt, punched him in the face, and threw him on the ground.
Ø He ran, jumped, and shouted at the playground.
** Commas can be omitted if the independent clauses are very short and closely connected.
Note: Some writers have argued that the conjunction (and, but, or) does the same thing as a comma. However, to avoid confusion, it is best to use the comma between the last two items.
I approved the proposal and he did too.
I like dancing and he likes skating.
Note: Comma Splice Error & Run on Sentence Error
If two independent clauses are connected without a conjunction but a comma, this type of error is called “comma splice”. If two independent clauses are connection without proper punctuations or conjunctions, this type of error is called “run-on sentence”.
Comma Splice Error:
I decided to run for city mayor, I believe that I have much to offer to the city. (X)
Run-on Sentence Error:
I decided to run for city mayor I believe that I have much to offer to the city. (X)
=> Correction: add comma and conjunction
I decided to run for city mayor, for I believe that I have much to offer to the city. (O)
=> Correction: Separate it into two simple sentences.
I decided to run for city mayor. I believe that I have much to offer to the city. (O)
=> Correction: add semicolon to separate the sentence.
I decided to run for city mayor; I believe that I have much to offer to the city. (O)
D. Use a comma to separate two or more adjectives (coordinate adjectives) when the word and can be inserted between them, and when the order of the adjectives can be reversed.
Ø Joanne has a most kind, sensitive, (and) untamed heart. (coordinate)
Ø I cannot find the white sporty car. (non-coordinate)
Ø She wore a bright red, fancy skirt. (bright & red: non-coordinate, red & fancy: coordinate)
** 版權所有 - Elisa