Writing - Comma 1

Unless you give me the tools, I won't be able to repair the car.
Use a comma after a subordinate/dependent clause when it begins a sentence. Other subordinate conjunctions:
after, although, as, because, before, even if, even though, if, in order that, once, provided that, rather than, since, so that, than, that, though, until, when, whenever, where, whereas, wherever, whether, while.
We don't usually put a comma after the main clause when a dependent (subordinate) clause follows it!
Common Errors:
She'll telephone you when she's finished . X no comma - WHEN is in the middle of the sentence
When she's finished, she'll telephone you. V WHEN begins the sentence

My aunt Fiona, whom you have just met, is a waiter.
We use a comma to separate non-defining relative clauses from the main clause. A non-defining relative clause describes a preceding noun by adding extra information about it.
Common Errors:
His new motorbike which he paid several thousand pounds is not running well. X commas required!
His new motorbike, which he paid several thousand pounds, is not running well. V two commas between extra information

To tell you the truth, he would do anything to win her heart.
A comma is used after phrases of more than three words that begin a sentence. If the phrase has fewer than three words, the comma is optional.
Common Errors:
On the day of the accident I left work early. X comma required!
On the day of the accident, I left work early. V the phrase has more than three words

Susan had a bad cold, so her father took her to the doctor.
A comma is used to separate two strong clauses joined by a coordinating conjunction (FANBOYS) for, and, nor, but, or, yet, so.
You can omit the comma if the clauses are both short.
Common Errors:
Hans is German but Julia is English. X comma required!
Hans is German, but Julia is English. V independent clause + independent clause

He's very good at Maths but still isn't able to answer correctly.
If the subject does not appear in front of the second verb, we do not use a comma.
Common Errors:
Steve ate breakfast and he drank coffee. X comma required!
Steve ate breakfast, and he drank coffee. V independent clause + independent clause
Steve ate breakfast and also drank coffee. V no comma - subject (HE) missing in the second part of the sentence!

She rushed to the station, but she was too late.
A comma is used to separate two strong clauses joined by a coordinating conjunction (FANBOYS) for, and, nor, but, or, yet, so.
You can omit the comma if the clauses are both short.
Common Errors:
Hans is German but Julia is English. X comma required!
Hans is German, but Julia is English. V independent clause + independent clause

My teacher criticised me because I didn't do my homework.
We don't usually put a comma after the main clause when a dependent (subordinate) clause follows it! Other subordinate conjunctions:
after, although, as, because, before, even if, even though, if, in order that, once, provided that, rather than, since, so that, than, that, though, until, when, whenever, where, whereas, wherever, whether, while.
Common Errors:
She'll telephone you, when she's finished. X WHEN is in the middle of the sentence
She'll telephone you when she's finished. V no comma - WHEN is in the middle of the sentence

I have to buy apples, oranges, grapes and bananas. | I have to buy apples, oranges, grapes, and bananas.
A comma is used to separate items in a list (nouns and adjectives). If you have more than two nouns or more than one adjective, you need to separate them with commas.
Common Errors:
He bought coffee, tea, beer, vodka. X AND must be included between BEER and VODKA
He bought coffee, tea, beer, and vodka. V the comma before AND is optional
He bought coffee, tea, beer and vodka. V AND must be included