Commas, Part I & II

Commas 1
Between items in a series

Chinese, English and Hindi are the three most widely used languages in the world.

Being comfortable with technology, working well with others, and knowing another language are important skills for today’s workers.


To keep numbers clear

Use commas to distinguish hundreds, thousands, millions, and so on

More than 104,000 people live in Kingston, the capital of Jamaica.

The population of the entire country of Liechtenstein is only 29,000.


In dates and addresses
On September 11, 2006, The World Trade Center in New York was attacked.

The school’s address is 10 Borrett Road, Mid-Levels, Hong Kong.



Commas 2

To set off non-restrictive phrases and clauses

People get drinking water from surface water or groundwater, which makes up only one percent of the earth’s water supply.
which makes up only one percent of the earth’s water supply is additional information – it is non-restrictive

Groundwater that is free from pollutants is rare.
that is free from pollutants is needed to complete the meaning of the basic sentence.


To set off titles or initials

Melanie Prokat, M.D., is our family doctor.

In the phone book she is listed as Prokat, M.



To set off interruptions

Interruptions can be identified through these tests:
You can leave them out of the sentence without changing the meaning
You can place them other places in the sentence without changing its meaning.

Our school, as we all know, is becoming overcrowded.

My history class, for example, has 42 students in it.

There are, indeed about 1,000 people in my school.

The building, however, has room for only 850 students.