Commas

Commas help to organize sentences and have many uses.
They can be used in the following ways:

DatesCommas are used to separate the parts of the date.  They are
used between two numbers, or between two words.

• December 12, 2006
  
• Monday, July 4
  

If the date is in the middle of a sentence, a comma goes after.
He arrived on June 10, 2007, and left three weeks later.

ListsCommas separate items in a list.

• I need bread, milk, eggs, and cheese.
  

ConjunctionsCommas go before a conjunction
(for, and, nor, but, or, yet, so)

• Jason spent fifteen minutes doing his homework, but it felt like an hour.
  
• I hadn't gone to class for most of the year, so I failed my exam.
  

AdjectivesCommas separate two adjectives before a noun.

• I bought a new, red car.
  
• The big, black dog is barking.
  

Interruptions or Non-Defining Relative ClausesCommas are used to separate a non-defining relative clause
from the rest of the sentence.  This is used to add extra
information, or make interruptions.

• The man, who had never been to Paris, was very excited.
  

After Introductory Words or Phrases
Use a comma after an introduction to a sentence including
times and transitional words.

• On Monday, the family travelled to Florida.
  
• While watching television, the children ate dinner and fought over their dessert.
  
• However, her bank account did not match her records.
  

Separate Place Names
Commas are used to separate two place names, most
commonly cities and countries.

• Tokyo, Japan
  
• Mexico City, Mexico