Commas: More Uses

GOAL:
To use commas correctly in sentence construction.

OBJECTIVES:
The student will be able to:

1. Distinguish between essential and non-essential clauses.
2. Identify relative clauses and appositives.
3. Set off non-essential clauses and phrases with commas.

LESSON INFORMATION:
In addition to setting off items in a series, independent clauses of compound sentences, and introductory phrases, there are other uses of the comma. Two other major uses of the comma are to set off:

- Non-essential clauses
- Appositives

Many sentences contain clauses that clarify information in the sentence. If the clause is essential, no commas are needed. If the clause is non-essential, it must be set off by commas.

Essential clause -
A clause that provides information needed for the clarity of the sentence. An essential clause cannot be omitted from the sentence without changing, or losing, the meaning of the sentence.

Non-essential clause -
A clause that provides additional information but is not necessary to the meaning of the sentence. A non-essential clause may be omitted from the sentence without changing the meaning of the sentence.

EXAMPLE 1:
A. Moisture in the air, which is also referred to as humidity, makes people feel warmer.
B. The weatherman who made so many incorrect predictions may be fired.

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Sentence A contains a non-essential clause set off by commas. The clause "which is also referred to as humidity" adds information to the sentence, but is not necessary for the meaning of the sentence.

Sentence B contains an essential clause so it is not set of by commas. If the clause "who made so many incorrect predictions" was omitted from the sentence, the meaning would be lost. Which weatherman may be fired??

Here are two hints to remember when trying to determine if a clause is essential or non-essential:

1. If the noun being described is a proper noun, the clause is usually non-essential. If the noun is a common noun, the clause is usually essential to help you identify the particular item being discussed.

2. Try omitting the clause. If the meaning of the sentence is still clear, the clause is non-essential and should be set off by commas. If meaning is lost or confusing, the clause is essential and no commas should be used.

ACTIVITY D-1:
Underline the clause or phrase in the following sentences and identify as essential or non-essential. If they are non-essential, set off with commas.

1. Louisiana a Gulf Coast state has many climatic problems involving humidity.

2. Other states that lie along warm bodies of water may also have humidity problems.

3. Homeowners who live in areas of high rainfall may have a problem keeping humidity out of their homes.

4. The National Air Conditioning Company which is located in most major cities in the state sells an air conditioning system guaranteed to help reduce humidity levels in the home.

5. Family members who allow excess humidity to collect in the home may be responsible for an uncomfortable living environment.

Many of the clauses used in the examples and exercises above are relative clauses. A relative clause is a clause beginning with a relative pronoun. The relative pronouns are:
who
whom
whose
which
what that whoever whomever

a. Any time you see these pronouns look for the relative clause to follow.
b. Determine if the clause is essential or non-essential to clarify the meaning of the sentence.
c. "That" always introduces an essential clause.
d. If the clause is non-essential, set off with commas.

ACTIVITY D-2:
Circle the relative pronoun in each sentence. Determine if the clause is essential or non-essential. If non-essential, set off with commas.

1. The homeowner that does not vent kitchen and bathroom steam to the outside will have a humidity problem.

2. An air conditioning unit which is correctly sized for the home will go a long way in preventing humidity problems. It will cool and dehumidify the air at the same time.

3. Mrs. Valin who is the local utility company representative reminds us that dishwashers and clothes dryers also produce much humidity in the home.

4. Skin that feels damp and clammy which is very uncomfortable is a sign of high humidity in the home.

5. Odors that increase in the humid home may signal rot or mildew.

en-m76

In addition to relative clauses, appositives and other explanatory expressions are usually set off with commas if determined to be non-essential.

Appositives: A noun used directly after another noun to mean the same thing. An appositive is considered non-essential and is set off with commas unless it is a single word closely connected to the preceding noun. See Example 2.

Example 2-
My neighbor, an energy conservationist, tries very hard to eliminate humidity and humidity-related problems from his home.

My wife Marilyn gets concerned about humidity when fog or frost forms on the windows of the house.

Explanatory expressions add information to the sentence. Some of these expressions include "of the Department of Natural Resources," or "such as cracking wood." You must determine if these expressions are necessary to the clarity of the sentence. If not, they are non-essential and should be set off with commas.

ACTIVITY R-1:
Circle all appositives and underline all explanatory expressions. Add all necessary commas.

1. During cold months like January central heating may be used in the home.

2. My sister Sylvia finds that her heating system dries the air in her home.

3. Mr. Sula of the utility company says it is common to have a lack of humidity in the air during the winter months.

4. Signs of too little moisture such as dry or cracking wood should signal the need for adding some humidity to the home.

ACTIVITY R-2:
Add any necessary commas in the following sentences. Look for: items in series, compound sentences, inverted order non-essential clauses, explanatory expressions and appositives. Tell WHY you placed each comma.

1. Nick Norman the local weatherman has given his forecast for today tomorrow and the weekend.
_______________________________________________________

2. Local citizens who are tired of the oppressive heat and humidity have decided to spend the weekend indoors and they will of course keep their air conditioners running.
_______________________________________________________
_______________________________________________________

3. Since the higher the humidity the warmer the air 95° feels warmer in Louisiana than in a dryer climate like Arizona.
_______________________________________________________
_______________________________________________________

RECOMMENDED READING:
Affordable Comfort - Louisiana Style: An Energy Saving Guide for Senior Citizens. Louisiana Department of Natural Resources, Baton Rouge, LA, n.d.

Moisture and Home Energy Conservation: How to Detect, Solve and Avoid Related Problems, U.S. Department of Energy, DOE/CE/15095-4, 1983.

INFORMATION CHECK
1. List five reasons to use a comma in a sentence.





2. Give some hints on determining whether a phrase is essential or non-essential.



3. Define appositive. Write two sentences using appositives. One should require commas, one should not.





4. Add commas where necessary in the following sentence. Tell WHY you placed each comma.

Mr. and Mrs. W. P. Smith my parents are aware that humidity which is also known as moisture in the air can make them feel warmer and they have made a concerted effort to vent humidity from their home using kitchen exhausts bathroom fans and a dryer vent.
___________________________________________________________
___________________________________________________________

5. Write a short paragraph explaining the relationship between heat, humidity, and air conditioning. Also mention ways of reducing humidity in the home.










TEACHER'S NOTES
Activity D-1:
1. Louisiana, A GULF COAST STATE, has many climatic problems involving humidity. (non-essential)

2. Other states THAT LIE ALONG WARM BODIES OF WATER may also have humidity problems. (essential)

3. Homeowners WHO LIVE IN AREAS OF HIGH RAINFALL may have a problem keeping humidity out of their homes. (essential)

4. The National Air Conditioning Company, WHICH IS LOCATED IN MOST MAJOR CITIES IN THE STATE, sells an air conditioning system guaranteed to help reduce humidity levels in the home. (non-essential)

5. Family members WHO ALLOW EXCESS HUMIDITY TO COLLECT IN THE HOME may be responsible for an uncomfortable living environment. (essential)

Activity D-2:
1. The homeowner that does not vent kitchen and bathroom steam to the outside will have a humidity problem.

2. An air conditioning unit which is correctly sized for the home will go a long way in preventing humidity problems. It will cool and dehumidify the air at the same time.

3. Mrs. Valin, who is the local utility company representative, reminds us that dishwashers and clothes dryers also produce much humidity in the home.

4. Skin that feels damp and clammy, which is very uncomfortable, is a sign of high humidity in the home.

5. Odors that increase in the humid home may signal rot or mildew.

Activity R-1:
1. During cold months, LIKE JANUARY, central heating may be used in the home.
2. My sister Sylvia finds that her heating system dries the air in her home.
3. Mr. Sula, OF THE UTILITY COMPANY, says it is common to have a lack of humidity in the air during the winter months.
4. Signs of too little moisture, SUCH AS DRY OR CRACKING WOOD, should signal the need for adding some humidity to the home.

Activity R-2:
1. Nick Norman, the local weatherman, has given his forecast for today, tomorrow, and the weekend.
appositive, items in a series

2. Local citizens who are tired of the oppressive heat and humidity have decided to spend the weekend indoors, and they will, of course, keep their air conditioners running.
essential relative clause, compound sentence, explanatory expression

3. Since the higher the humidity the warmer the air, 95° feels warmer in Louisiana than in a dryer climate, like Arizona.
inverted sentence, explanatory expression

Answers to Information Check:
1. Between items in a series, in compound sentences, in sentences with inverted order, to set off non-essential relative clauses, to set off most appositives and some explanatory phrases.

2. A phrase or clause is essential if it adds necessary information to the sentence and if the sentence is unclear without that information. A clause is non-essential if the sentence is still clear with that information omitted.

3. An appositive is a noun found directly after another noun that simply renames it. Examples of sentences follow:
a. My neighbor, Lisa Siven, is very energy conscious.
b. My brother Nathan pays enormous monthly utility bills.

4. Mr. and Mrs. W. P. Smith, my parents, are aware that humidity, which is also known as moisture in the air, can make them feel warmer, and they have made a concerted effort to vent humidity from their home using kitchen exhausts, bathroom fans, and a dryer vent.
appositive, non-essential relative clause, compound sentence, items in a series

5. Example paragraph follows:

Humidity, or moisture in the air, makes a person feel warmer. For example, a home that normally feels cool at 78° may feel warm if there is high humidity in the home. An air conditioning system that is properly sized for the home will help reduce humidity while cooling the home. Other ways to prevent humidity in the home are to reduce water around the home and to vent all humidity produced in kitchens and bathrooms to the outside.

Comments or questions to: TechAsmt@LA.GOV

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