Simple, Compound and Complex Sentences

Reference notes from: Aspects of Grammar – a handbook for writing assessment (2005 New South Wales Departmant of Education and Training)

A sentence is a group of words that makes complete sense. In writing it is marked at its beginning with a capital letter and at its end with a full stop, question mark or exclamation mark.

Sentences serve the following purposes:

  • To make statements (declaratives): The girl played basketball.
  • To ask questions (interrogatives): When does the game begin?
  • To utter commands (imperatives): Aim the ball higher.
  • To deliver exclamations (exclamatives): What a goal!

Simple, Compound and Complex Sentences

Sentences are categorised into three types – simple, compound and complex – according to the number and type of clauses they contain.

Simple sentences

A simple sentence consists of a single independent or main clause. It does not have another clause functioning as one of its elements. A simple sentences may also include one or more phrases. For example:

main clause         prepositional phase

Kim walked along the track.

    adverbial phrase                                               main clause

At exactly 9 pm every night, David turned off the lights.

Compound Sentences

In compound sentences, there are two or more independent clauses that are linked. Each independent or main clause is able to stand on its own and the meanings of all clauses are of equal importance.

Because compound sentecnes coordinate independent clauses equally, they tend of use the additive conjunctions and and or, or the contrastive conjunction but.

For example:

John was getting tired but he was determined to finish his bushwalk.

John ate his lunch and then he continued on his way.

Complex Sentences

A complex sentence consists of one (or more) main clause/s and one (or more) dependent clause/s.

A dependent clause provides a separate piece of information to the main clause but is dependent on the main clause to make meaning or sense. For example, consider the dependent calsues in bold type below. Neither could stand on its own. Each depends on on ideas in the main clause for its meaning.

I sat down on a cardboard box that promptly collapsed under my weight.

For as long as she could remember, Olivia had enjoyed playing piano.

Complex sentences can have dependent clauses in a range of logical relationships with the main clause. Conjunctions such as when, because, although and if indicate the nature of the relationship between some dependent clauses and the main clause.

Complex sentences can include both complex and compound elements. Consider the example below.

first main clause                second main clause                         dependent clause

Jill opened the map and studied it carefully so that she knew exactly where to go.

The coordinating conjunction and links the compound elements of this sentence,  while the subordinating conjunction so that links the complex element.

Adverbial clauses

Adverbial clauses provide further information about time, place and manner in which the verb (the action) occurs. Adverbial clauses usually begin with a conjunction that indicates their relationship with the main clause.

Different types of subordinating conjunctions include:

  • Place: where, whenever
  • Time: after, before, when, just as, as though, like
  • Causal: because, since, as, therefore, if, otherwise, still despite
  • Concessional: although, though, even though, even if
  • Comparative: as, as if, as though, so… that, on the other hand
  • Sequential: firstly, (secondly, thirdly etc), finally, then, when, next, here, now, lastly, meanwhile

Adjectival clauses

Adjectival clauses (sometimes called relative clasues) qualify or add meaning to nouns or nominal groups in the main clause. Relative clauses are usually introduced by relative pronouns such as who, which, that, whose, whom.

Katya, who had never enjoyed the outdoors, was forced to go for a bushwalk.

I read the book Mr Wilson gave me. (which/that has been ellipsed)

Non-finite dependent clasues

Dependent clauses do not need to have finite verbs (verbs with a subject and tense). Non-finite clauses contain the non-finite form of the verb: the infinitive ‘to…’ (to start, to forget, to play) or the participle forms which end in -ing or -ed.

Non-finite clauses may function as adjectival or adverbial clauses in a sentence.

Dependent clause in first position

Sometimes a writer places a dependent clause before the main clause in order to emphasise this part of the sentence. In assessing students responses in NAPLAN, this type of complex structure is considered separately as it demonstrates a more sophisticated control of writing.

Dependent clauses in first position are usually adverbial clauses or non-finite clauses.

Before I knew it, it was lunchtime. (dependent adverbial clause in first position)

To get to the beach, I have to catch three buses. (dependent non-finite in first position)

Knowing how badly she needed it, I gave her some water. (dependent non-finite clause in first position)

EALD Language and Literacy Levels