This document provides information about different types of dependent clauses that can be used in sentences, including adverbial clauses, nominal clauses, and relative clauses. It discusses how to punctuate sentences containing these clauses, explaining that adverbial clauses at the beginning of a sentence should be separated by a comma, while other types of clauses are not usually separated by commas. Examples are provided to illustrate the different clause types and proper punctuation. Exercises at the end ask the reader to insert commas in sentences containing various clauses.

1. Introductory phrases
Adverbial clauses
Nominal clauses
Relative clauses

2. You have no issues in punctuating the beginning of a sentence when
you begin directly with its subject, as I did this one. However, as with
this one, when a sentence forces a reader to plough through several
introductory words, phrases, and clauses, especially when they have
their own internal punctuation and readers might be confused by it all
(as you may be right now), you can forget trying to punctuate it right:
revise it.
beginnings adverbial clauses nominal clauses relative clauses
Introductory phrases

3. You have no issues in punctuating the beginning of a sentence when
you begin directly with its subject, as I did this one. However, as with
this one, when a sentence forces a reader to plough through several
introductory words, phrases, and clauses, especially when they have
their own internal punctuation and readers might be confused by it all
(as you may be right now), you can forget trying to punctuate it right:
revise it.
EXPLANATION
If you need to use an expression that comes
before the independent clause, use a comma.
beginnings adverbial clauses nominal clauses relative clauses
Introductory phrases

4. EXAMPLES
Therefore, I plan to quit smoking.
Nervously, I threw away my cigarettes.
As a result, I feel terrible right now.
After 16 years of smoking, it is not easy to quit.
Having smoked for 16 years, I find it diffucult to quit.
beginnings adverbial clauses nominal clauses relative clauses
Introductory phrases

5. An adverbial clause is a dependent clause that functions as an
adverbial. It can tell when, where, why, how, how long, how far, how
often, and for what purpose.
Adverbial clauses are introduced by: because, when, whenever, while,
as soon as, after, since, as, before, until, where, wherever, as, as if, so
that, although, even though, though, if, unless, etc.
beginnings adverbial clauses nominal clauses relative clauses
Adverbial clauses

6. When an adverbial clause comes first in a sentence, put a comma after
it. When an adverbial clause follows an independent clause, do not
separate the clauses with a comma.
Because she was late every day, she lost her job.
She lost her job because she was late every day.
EXPLANATION
Adverbial clauses function as adverbials, so they should appear after the
independent sentence (to follow the traditional word order: subject – verb –
object – adverbials). If they appear at the beginning, use a comma because
they break the traditional word order (the same way as introductory phrases).
beginnings adverbial clauses nominal clauses relative clauses
Adverbial clauses
Adverbial clause
Adverbial clause
Independent clause
Independent clause

7. EXAMPLES
Farmers use chemical pesticides so that they can fet higher crop yields.
Although I had studied all night, I failed the test.
If you study, you will get good grades.
Whenever I had to speak in front of people, I was paralyzed by fear.
The men hunted game while the women gathered plants.
NOTICE: “So that” introduces an adverbial
clause, and it is not introduced with a comma;
“so” introduces an independent clause, and it
is separated with a comma.
beginnings adverbial clauses nominal clauses relative clauses
Adverbial clauses

8. A nominal clause is a dependent clause that functions as a noun. It is
often part of an independent clause, where it can be a subject or an
object.
subject
What the newspaper reported was incorrect.
object
People once believed that the world was flat.
EXPLANATION:
Never use a comma
to separate a
nominal clause
from the
independent
clause.
beginnings adverbial clauses nominal clauses relative clauses
Nominal clauses

9. EXAMPLES
I am sure that the address is correct.
It is certain that Earth is getting warmer.
The class was surprised that the instructor canceled the final exam.
Do you know who the interpreter for the Russian leader was?
The students want to know if the test is easy.
Police do not know who committed the robbery.
beginnings adverbial clauses nominal clauses relative clauses
Nominal clauses

10. A relative clause is a dependent cluase that functions as an adjective.
That is, it gives more information about a noun or pronoun.
Relative clauses are introduced by: who, whom, which, that, whose,
where.
Everyone who studied for the exam passed it easily.
Mayor Pyle, whom I voted for, lost the election.
beginnings adverbial clauses nominal clauses relative clauses
Relative clauses

11. Defining relative clauses are necessary to identify its antecedent for
the reader. Do not use commas with defining clauses.
The professor who teaches my biology class won a Nobel Prize two
years ago. He won the Prize for research that might lead to a cure for
AIDS.
Which professor won a Nobel Prize two years ago? The
clause who teaches my biology class is necessary to
identify the professor.
For which research did he win the prize? We need the clause
that might lead to a cure for AIDS to tell us.
beginnings adverbial clauses nominal clauses relative clauses
Relative clauses

12. Non-defining relative clauses are not necessary to indentify its
antecedent; they merely give the reader some extra information about
it. Because you can omit a non-defining relative clause without loss of
meaning, separate if from the rest of the sentence with commas.
Professor Jones, who teaches my biology class, won a Nobel Prize two
years ago. He won the prize for his research into the structure of T-
cells, which might lead to a cure for AIDS.
The person who won a Nobel Prize is identified by his name, so
the clause who teaches my biology class is extra, unnecessary
information about Professor Jones. If it were omitted, we would
still know which person won the Nobel Prize.
We already know which research he won the prize for: his
research into the structure of T-cells. The information which
might lead to a cure for AIDS is not necessary to identify the
research; I merely gives us extra information about it.
beginnings adverbial clauses nominal clauses relative clauses
Relative clauses

13. EXAMPLES OF DEFINING RELATIVE CLAUSES
Families whose incomes are below a certain level pay no income tax.
She loaned her car to someone whom she did not know.
I studied algerba with a professor whose name I have forgotten.
The subject that I enjoyed the most is algebra.
The class that meets in the next room is very noisy.
Note: “That” is only used in defining relative clauses.
It cannot be used in non-defining relative clauses.
beginnings adverbial clauses nominal clauses relative clauses
Relative clauses

14. EXAMPLES OF NON-DEFINING RELATIVE CLAUSES
Apple Computer, whose Macintosh computer changed computing, was
started by two men working in a garage.
Her husband teaches algebra, which I enjoy the most.
On November 9, 1989, when the wall was torn down, their lives
changed again.
The Saudi Arabian city of Mecca, where Mohammed was born, is the
holiest city in Islam.
I did not work last week, when I had my final exams.
beginnings adverbial clauses nominal clauses relative clauses
Relative clauses

15. EXERCISES
INSERT COMMAS IF NECESSARY
1. Most people shop where they get the lowest prices.
2. In order that consumers can enjoy unblemished fruits and vegetables farmers spray the
fields with chemicals.
3. He thinks that further research will prove that eating richly spiced foods can have long-
term effects.
4. Since many Europeans live, work, and shop in the same locale they are quite accustomed
to riding bicycles, trains, and streetcars to get around.
5. Kuwait which is a small country in the Middle East is in first place.

16. EXERCISES
INSERT COMMAS IF NECESSARY
6. Before people in the US moved to cities they grew most of their own food.
7. It was a thrilling experience to meet the author of the book that we had been reading all
semester.
8. Whether the professor will reschedule the exam is uncertain.
9. The sun which in 40 minutes can produce enough solar energy to meet humankind’s
needs for a year is one of Earth’s potential sources of power.
10. Experts agree that neither sex is more intelligent than the other.

17. EXERCISES
INSERT COMMAS IF NECESSARY
11. I enrolled in a speech class because I need to make speeches for career advancement.
12. She does not know when he arrived.
13. A medical computer is a machine that analyzes the results of laboratory tests and
electrocardiograms.
14. The bus’s engine sounds as if it is going to collapse at any moment.
15. It is necessary that each salesperson work longer hours.

18. REFERENCES
Oshima, Alice: Writing Acedemic English
Williams, Joseph M.: Style: Lessons in Clarity and Grace
McCarthy, Carter: Cambridge Grammar of English