In grammar, clause structure refers to the classification of sentences based on the number
and kind of clauses in their syntactic structure.
Such division is an element of traditional grammar.
A simple sentence consists of only one clause.
A compound sentence consists of two or more independent clauses.
A complex sentence has at least one independent clause plus at least one dependent clause.
A set of words with no independent clause may be an incomplete sentence, also called
a sentence fragment.
A sentence consisting of one or more dependent clauses plus two or more independent clauses
may be called a complex-compound sentence or compound-complex sentence.
Sentence 1 is an example of a simple sentence.
Sentence 2 is compound, while sentence 3 is complex.
Sentence 4 is compound-complex.
Example 5 is a sentence fragment.
I like pumpkin pie.
I don't know how to bake, so I buy my sweets.
I enjoyed the apple pie that you bought for me.
The dog lived in the garden, but the cat, who was smarter, lived inside the house.
What a silly dog.
The simple sentence in example 1 contains one clause.
Example two has two clauses, combined into a single sentence with the coordinating conjunction
so.
In example 3, I enjoyed the apple pie is an independent clause, and that you bought for
me is a dependent clause; the sentence is thus complex.
In sentence 4, The dog lived in the garden and the cat lived inside the house are both
independent clauses; which was smarter is a dependent clause.
Example 5 features a noun phrase but no verb.
It is not a grammatically complete clause.
Simple sentences A simple sentence structure contains one independent
clause and no dependent clauses.
I run.
This simple sentence has one independent clause which contains one subject, I, and one predicate,
run.
The girl ran into her bedroom.
This simple sentence has one independent clause which contains one subject, girl, and one
predicate, ran into her bedroom.
The predicate is a verb phrase that consists of more than one word.
In the backyard, the dog barked and howled at the cat.
This simple sentence has one independent clause which contains one subject, dog, and one predicate,
barked and howled at the cat.
This predicate has two verbs, known as a compound predicate: barked and howled.
This compound verb should not be confused with a compound sentence.
In the backyard and at the cat are prepositional phrases.
Compound sentences A compound sentence is composed of at least
two independent clauses.
It does not require a dependent clause.
The clauses are joined by a coordinating conjunction, a semicolon that functions as a conjunction,
a colon instead of a semicolon between two sentences when the second sentence explains
or illustrates the first sentence and no coordinating conjunction is being used to connect the sentences,
or a conjunctive adverb preceded by a semicolon.
A conjunction can be used to make a compound sentence.
Conjunctions are words such as for, and, nor, but, or, yet, and so.
The use of a comma to separate two independent clauses without the addition of an appropriate
conjunction is called a comma splice and is generally considered an error.
Complex and complex-compound sentences
A complex sentence has one or more dependent clauses.
Since a dependent clause cannot stand on its own as a sentence, complex sentences must
also have at least one independent clause.
A sentence with two or more independent clauses plus one or more dependent clauses is called
compound-complex or complex-compound.
In addition to a subject and a verb, dependent clauses contain a subordinating conjunction
or similar word.
There are a large number of subordinating conjunctions in English.
Some of these give the clause an adverbial function, specifying time, place, or manner.
Such clauses are called adverbial clauses.
When I stepped out into the bright sunlight, from the darkness of the movie house, I had
only two things on my mind.
This complex sentence contains an adverbial clause, When I stepped out into the bright
sunlight from the darkness of the movie house.
The adverbial clause describes when the action of the main clause, I had only two things
on my mind, took place.
A relative clause is a dependent clause that modifies a noun or noun phrase in the independent
clause.
In other words, the relative clause functions similar to an adjective.
Let him who has been deceived complain.
You, who have never known your family, see them standing around you.
In the first example, the restrictive relative clause who has been deceived specifies or
defines the meaning of him in the independent clause, Let him complain.
In the second example, the non-restrictive relative clause who have never known your
family describes you in the independent clause, You see them standing around you.
A noun clause is a dependent clause that functions like a noun.
A noun clause may function as the subject of a clause, or as a predicate nominative
or an object.
What she had realised was that love was that moment when your heart was about to burst.
In this sentence the independent clause contains two noun clauses.
The noun clause What she had realized serves as the subject of the verb was, and that love
was that moment serves as complement.
The sentence also contains an adverbial clause, when your heart was about to burst.
Incomplete sentence An incomplete sentence, or sentence fragment,
is a set of words which does not form a complete sentence, either because it does not express
a complete thought or because it lacks some obligatory grammatical element, such as a
subject or a verb.
A dependent clause without an independent clause is one example of an incomplete sentence.
Some prescriptive grammars consider sentences starting with a conjunction such as but or
and as incomplete sentences, but this style prescription has "no historical or grammatical
foundation".
Computer grammar checkers often highlight incomplete sentences.
If the context is clear from the rest of the paragraph, however, an incomplete sentence
may be considered perfectly acceptable English.
References
External links "Sentence Types".
Online Writing Lab.
Purdue University.
1995.
Retrieved 2 February 2014.
Campos Noguera, José Manuel.
"Complex sentences".
English Post: English Language Learning and Teaching.
Retrieved 2 February 2014.
"Forming Complex Sentences with Subordinating Conjunctions".
"Independent and Dependent Clauses".