[English Writing] commas (,) usage

Basic Rules

For more, please refer to grammarbook.com

R1. Dependent clause + Main clause

When starting a sentence with a weak clause, use a comma after it. Conversely, do not use a comma when the sentence starts with a strong clause followed by a weak clause. (from grammarbook.com)

Examples:

• If I ever complete my PhD successfully, I will be amazed.
  • I will be amazed if I ever complete my PhD successfully.
• When I use it, the e-mail always breaks down.
  • The e-mail always breaks down when I use it.

R2. Adverbs that relate to the whole sentences

Examples:

• However, some researches adopt a markedly different approach.
• Superisingly, he did not go to the school yesterday.

R3. Speech + comment

Examples:

• "Paul Klee," he remarked, "was the first person to acutally paint commas".

R4. When a sentence is 'broken open' in the middle

Examples:

• Some researches, on the other hand, adopt a different approach.
• There are, it seems, two different solutions to the enthanasia problem.

R5. Items in lists

Use commas to separate words and word groups with a series of three or more.

Examples:

• Many essays are over-long, convoluted and boring. [UK]
• Many essays are over-long, convoluted, and boring. [US]
• Do not steal, copy, or plagiarise ideas.

R6. Separate two adjectives when end can be inserted between them

Examples:

• He is a strong, healthy man.
  • He is a strong and healthy man.
• He is a lonely, young boy.

R7. Separate day and month from the year when writing date.

Examples:

• I will have a business travel from May 15th, 2011.
• I will have a business travel from May 2011. (If day, month or year is ommitted, no comma)