| Rule 1. |
To avoid confusion, use commas to separate words and word groups with a series of three or more. |
| Example: |
My $10 million estate is to be split among my husband, daughter, son, and nephew. Omitting the comma after son would indicate that the son and nephew would have to split one-third of the estate. |
| Rule 2. |
Use a comma to separate two adjectives when the word and can be inserted between them. |
| Examples: |
He is a strong, healthy man. |
| We stayed at an expensive summer resort. You would not say expensive and summer resort, so no comma. |
|
| Rule 3. |
Use a comma when an -ly adjective is used with other adjectives. |
| NOTE: |
To test whether an -ly word is an adjective, see if it can be used alone with the noun. If it can, use the comma. |
| Examples: |
Felix was a lonely, young boy. |
| I get headaches in brightly lit rooms. Brightly is not an adjective because it cannot be used alone with rooms; therefore, no comma is used between brightly and lit. |
|
| Rule 4. |
Use commas before or surrounding the name or title of a person directly addressed. |
| Examples: |
Will you, Aisha, do that assignment for me? |
| Yes, Doctor, I will. |
| NOTE: |
Capitalize a title when directly addressing someone. |
|
Source: http://www.grammarbook.com/punctuation/commas.asp
From: McGraw Hill’s 2010 GRE :
English possessive determiners (my, our, your, his/her/its, their – sometimes called possessive adjectives) must match the person and number of the possessor and not the noun phrase to which they are linked.
Richard likes his hot dogs with lots of relish. The word his is third person singular to match with Richard, NOT third person their to match with hotdogs.