In this lesson,
you'll learn two ways to classify sentences, by structure and by function,
and you'll learn how your choice of structure and/or function affects
the meaning you're trying to convey.
Classifying
Sentences by Structure
The structure
of a sentence refers to the types of parts in the sentence as
well as the way(s) these parts are put together. There are four basic
structures for English sentences: simple, compound, complex, and compound-complex.
A simple
sentence consists of a single independent clause, which itself contains
a subject (noun) part, a predicate (verb) part, and an appropriate
mark of punctuation. (An object part, which generally follows the
predicate part, is optional.) Simple sentences can range from very
short to very long independent clauses:
Lisa drove.
Lisa drove
her car from Minneapolis to Milwaukee.
Lisa drove
her 13-year-old, rusty Mustang, which had 150,000 miles and no air
conditioning, from Minneapolis to Milwaukee on a steamy July day.
All three of
these sentences consist of a subject, a predicate, and an appropriate
mark of punctuation (and the latter two also contain an object). Regardless
of length, because these sentences consist of a single independent
clause, they are simple sentences.
A compound
sentence consists of two or more independent clauses. These clauses
are connected either with a semi-colon or with a comma and coordinating
conjunction such as for, and, nor, but, or, yet, so (think
"fanboys" to remember these):
Toby wanted
to become a doctor; he applied to medical school.
Toby wanted
to become a doctor, so he applied to medical school.
Both of these
sentences contain two independent clauses—Toby wanted to become
a doctor, and he applied to medical school. In the first
sentence, these two clauses are connected with a semi-colon, which
indicates that a relationship exists between the two but doesn't specify
the nature of that relationship; in the second sentence, the clauses
are connected with a comma and the coordinating conjunction "so,"
which indicates that a relationship exists between the two, and that
this relationship is one of "cause/effect."
A complex
sentence consists of one independent clause connected to one or more
dependent clauses. A dependent clause, like an independent
clause, contains a subject and a predicate; however, the dependent
clause is preceded by a subordinating element, such as after,
because, during, even though, however, if, since, though, unless,
and while.
Dependent
Clause: Because I couldn't fall asleep last night
Complex Sentence:
Because I couldn't fall asleep last night, I'm very tired today.
I'm very tired today because I couldn't fall asleep last night.
The dependent
clause begins with the subordinating word "because"; so, although
it contains the subject "I" and the predicate "could (not) fall,"
it is not a complete sentence. In the complex sentence, however, the
dependent clause is connected to the independent clause I'm very
tired today; consequently, this is a complete sentence.
Note:
When the dependent clause comes before the independent clause, a comma
must follow the dependent clause. When the dependent clause comes
after the independent clause, no comma is needed.
A compound-complex
sentence consists of two (or more) independent clauses and one
(or more) dependent clauses:
I am hungry
although I just ate breakfast, but if I don't eat again soon, I'm
going to faint.
This compound-complex
sentence can be broken down into its component parts, as follows:
I am hungry
(independent clause) although I just ate breakfast (dependent clause beginning with
the subordinate word "although") , but (coordinating conjunction connecting the independent
clauses) if I don't eat again soon (dependent clause beginning with
the subordinate word "if") I'm going to faint (independent clause)
In general,
writers choose a simple sentence structure to convey ideas that can
be easily understood; when ideas are more complex, or when specific
relationships exist among ideas, writers choose to use a more complex
sentence structure. It is likely that as you progress in your college
classes and take more challenging college courses, you will begin
to write in more complex sentences that will help you to express your
more complex thoughts.
Classifying
Sentences by Function
The function
of a sentence refers to the purpose in communicating an idea. There
are four basic types of functions for English sentences: declarative,
interrogative, exclamatory, and imperative.
A declarative
sentence is used to indicate a statement. Most sentences used
in communication are declarative:
He wanted
to leave, but he couldn't go.
Because the
second offer was low, they decided to accept the first bid.
An interrogative
sentence is used to indicate a question. An interrogative sentence
is noted by its ending punctuation, a question mark:
Did he really
want to leave?
Why did they
decide to accept the first bid, rather than the second?
An exclamatory
sentence is used to indicate an exclamation, or an expression of thought
mixed with strong emotion. Like an interrogative sentence, an exclamatory
sentence is noted by its ending punctuation, an exclamation point:
He wanted
to leave!
They accepted
the first bid!
An imperative
sentence is used to indicate a request or a command. An imperative
sentence will always use the second-person "you" form in the subject
and the predicate:
You should
leave.
Accept the
first bid, not the second one.
Note:
In an imperative sentence, the second-person pronoun "you" may be
omitted from the construction of the sentence. In high school, you
may have heard this sentence construction called a "command" with
the "you" understood.
In general, writers
choose the functional type of sentence based upon their purpose and
audience for writing. If writers want to ask a question, make an exclamation,
or issue a command, they choose the interrogative, exclamatory, or
imperative type, respectively. In most academic writing situations,
however, writers tend to rely most heavily upon the declarative sentence
for presenting and explaining ideas.
Exercise
1: In the paragraph below, label the following sentences according
to their structural type: simple, compound, complex, or compound-complex.
Type your answers in the text box provided, then click Compare to
check your answers against ours.
(1) Bored with
her current level of responsibilities, Marcia decided to find a
new job. (2) She examined newspapers in her community to learn of
possible openings, and she checked out employment sites on the Internet.
(3) Despite all of her searching, she didn't find anything that
interested her. (4) So, she decided to open her own business. (5)
She called upon her friends to help her get started, and although
they were busy, they agreed to help her in any way they could. (6)
Three weeks after she decided to quit her job, Marcia had secured
a storefront site and, because she had finished decorating her space
in a professional manner, she was open for business.
Exercise
2: In the paragraph below, label the following sentences according
to their functional type: declarative, interrogative, exclamatory,
or imperative. Type your answers in the text box provided, then
click Compare to check your answers against ours.
(1) Once she
turned four years old, she wanted to ride her bicycle by herself.
(2) But she wondered: Can I really do it? (3) Or will I hurt myself?
(4) Undaunted by the possibility of injury, she climbed upon her
yellow banana seat, and she grabbed the handlebars with a death
grip. (5) She pedaled for a few feet, but she soon felt her right
foot slip. (6) Oh no — she was going to fall! (7) She braced
herself as she tumbled onto the gravel road. (8) After she landed,
she had only one message for herself. (9) Get up and try it again.
Summary
Sentences can
be classified according to their structure and their function. In
terms of structure, a sentence can be classified as simple, compound,
complex, or compound-complex. In terms of function, a sentence can
be classified as declarative, interrogative, exclamatory, or imperative.
As writers, it's important to know about the various structures and
functions of sentences so a conscious choice about the structure and
function best suited for conveying a particular meaning can be made.
Since different structures and functions indicate different things,
it's essential for writers to choose those that complement the message
they're trying to convey.
