Sentence structure, parts and types of sentences

In a nutshell

Sentences are made up of sentence elements, also known as clause elements. These are the parts of a sentence and are important to know. In this summary, you will learn more about sentence elements, sentence types and what sentences can do.

Five sentence elements

There are five sentence elements (clause elements) that will be explained, namely subject, verb, object, complement and adverbial - SVOCA.

Subject

A sentence with one clause, i.e. a main clause, is known as a simple sentence. In a simple sentence, only one thing is being expressed. A simple sentence usually contains a subject which can either be a single word, a short phrase or a substantial phrase.

Example

The subject of the following simple sentence: "Ladybirds protect plants" can be written in the following ways:

subject as:	Examples
	subject	predicate
Single word	Ladybirds	protect plants.
Short phrase	Local ladybirds	protect plants.
Substantial phrase	Many species of local ladybirds	protect plants.

Verb

The subject will then need a verb which, as a reminder, describes actions or states. For a sentence to be a sentence, it must contain a verb. A verb can be a single word or a sequence of words (called a verb phrase) which includes a main verb and a number of auxiliary verbs.

Verb as:	examples
	subject	verb	object
Single word	Ladybirds	protect	plants.
Sequence of words (verb phrase)	Many species of local ladybirds	have been protecting	plants.

Object

Many verbs then require an object which can either be a single word, a short phrase or a substantial phrase.

object as:	Examples
	Subject	verb	object
Single word	Many species of local ladybirds	protect	plants.
Short phrase	Many species of local ladybirds	protect	various plants.
Substantial phrase	Many species of local ladybirds	have been protecting	various plants and crops.

Objects can also be separated into direct objects (dO) and indirect objects (iO). The direct object is the thing acted upon by the subject while the indirect object receives the action.

Examples

subject	verb	dO	iO
Atif	threw	the ball.
Atif	threw	the ball	to Sam.

Complement

A complement is a sentence element that tells you more about the subject or the object. To have a complement, you usually need the verb 'to be' (am, is, are, was, were).

Example

subject	verb	complement
The flowers	are	aromatic.

The verb 'are' in the sentence above is called a copular verb. It connects the subject (The flowers) to the complement (aromatic). The verb 'to be' is not the only copular verb though; verbs like appear, seem, sound, smell, taste etc. are also examples of copular verbs.

Examples

subject	copular verb	complement
The flowers	smell	wonderful.
The flower petals	taste	sour.

Adverbial

The part of a sentence that tells you where, when or how something happens is called the adverbial and can be moved around within the clause/sentence.

subject	adverbial	verb	object
She	aggressively	threw	the ball.
subject	verb	object	adverbial
She	watched	the football game	yesterday.
adverbial	subject	verb	object
In the meadow,	we	saw	flowers.

Note: Adverbials don't necessarily contain an adverb. In the third example above, the phrase 'In the meadow' functions as an adverbial of place but it is made up of a preposition (In), a determiner (the) and a noun (meadow).

Sentence types

There are three sentence types you need to learn: simple, compound and complex sentences.

Sentence types	definition	examples
Simple sentence	A simple sentence is just a normal sentence. In other words, it is a main clause that contains a subject and a verb.	Ladybirds protect plants.
Compound sentence	A compound sentence is just two simple sentences (i.e. two main clauses) compounded (combined) using coordinating conjunctions which are the conjunctions, for, and, nor, but, or, yet and so. Each clause has the same weight or importance.	[Ladybirds protect plants], and [consume crop-eating insects.]
Complex sentence	A complex sentence consists of a main clause and a subordinate clause. Subordinate clauses provide sentences with extra detail; they cannot function as complete sentences by themselves. Subordinate clauses usually begin with subordinate conjunctions (unless, before, when, because etc.). In this type of sentence, one event is thought to be more important than the other.	Ladybirds are beneficial for the environment because they prey on tiny, harmful insects. OR Because ladybirds prey on tiny, harmful insects, they are beneficial for the environment.

In the second complex sentence example, "Because ladybirds prey on tiny, harmful insects, they are beneficial for the environment.", notice how the subordinate clause is put at the front of the sentence; this is called a left-branching sentence (the subordinate clause branches off left from the main clause) or a periodic sentence (the main clause is saved last in the sentence). The order of all these elements in a sentence is what is referred to as syntax.

The subordinate clause in the second complex sentence example that was just discussed can also be written without the conjunction altogether to form a non-finite subordinate clause. It can be replaced with a non-finite verb; i.e. verbs that do not show tense, person or number. As a reminder, there are three types of non-finite verbs: gerunds, participles and infinitives.

Example

Because ladybirds prey on tiny, harmful insects, they are beneficial for the environment.

\to

By preying on tiny, harmful insects, ladybirds are beneficial for the environment.

"Preying" in the example above is a non-finite verb, more specifically a gerund and changes the subordinate clause to a non-finite subordinate clause.

Another type of sentence to take note of is a minor sentence. This is either a phrase or a subordinate clause that's used as a complete sentence. Minor sentences are used very often in conversation and writers use them to create a casual feel or to surprise the reader.

Examples

The more the merrier.

First come, first served.

More coffee?

Finally, a sentence can also be a compound-complex sentence. This means you can have a main clause with a subordinate clause as well as a coordinate clause (a clause beginning with a coordinating conjunctions) all in one.

Example

Because ladybirds prey on tiny, harmful insects, they are beneficial for the environment and make the lives of farmers easier.

What sentences do

Sentences and sentence types can serve different purposes in writing.

What different sentence types do

simple sentences:

can be used to stand out from longer sentences or placed in between longer sentences to break the rhythm.

appear in children's literature, more specifically books for learning to read.

can make a text too 'clunky' when too many are used.

compound sentences:

improve fluency in a text.

are often found in speech as part of a narrative or storytelling.

can go on forever.

complex sentences:

are easy to read if the main clause is written first.

are harder to read if the subordinate clause is written first.

are difficult to read if there are too many of them or if the sentence is too long.

help writers, like the other sentence types, vary the style, pace and structure of their writing.

What sentences do

There are four kinds of sentences:

sentence kind	structure and purpose	examples
Declarative sentences (statements)	The subject generally comes in front of the verb. These sentences are more common in informational texts and show assurance.	London is the capital of England.
Interrogative sentences (questions)	The subject usually comes after the verb. Questions usually require an answer. They keep a conversation going. They can show power or a lack of power, depending on the context or speaker. They can be used to liven up informative writing and make persuasive writing more engaging. They can be used to make commands seem softer and less aggressive. They can also be in the form of tag questions; added to the end of a statement to make a sentence more inclusive.	What is the capital of England?
Imperative sentences (commands)	These sentences typically begin with a verb and leave out the subject. They are usually found in advisory texts. They can be softened if they're incorporated into subordinate clauses.	Keep quiet!
Exclamatory sentences (exclamations)	These sentences express emotion such as excitement, joy, shock or anger.	Help!