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Describing sentences: basic terminology

There are three main types of sentences: simple, compound and complex.

1. Simple sentences

Sentences are made up of one or more clauses. A simple sentence consists of one main clause, which usually looks like this:

  • subject (who or what actions the verb) + verb (a state or action) + object (who or what is affected by the verb), e.g.

(1) || The university || funded || the research group ||.

(2) || The study || looked into || the causes of corrosion ||.

  • subject + verb + (+ object) + complement (information about the subject or object of the clause), e.g.

(3) || She || is || a civil engineer ||.

(4) || They || made || him || head of department ||.

  • subject + verb + adverbial (information about the situation), e.g.

(5) The book || has undoubtedly contributed || to the debate on sustainability.

(6) || In the early 20th century, || many advances || were made || in the field of physics.

(7) || When conducting trials on mice, || they || found || the drug || to be effective and harmless.

Long and complex clause elements

A simple sentence can be very short and ‘simple’, but sometimes the different parts of the sentence (subject, object, complement, adverbial) can themselves be long and complex, for example this sentence that consists of a subject + verb + complement:

|| A systematic controller synthesis for heterogeneous multi-agent systems || can be || an important tool for the control of modern large-scale networks ||.

It is sometimes a good choice to have these longer, complex elements in a sentence, as they can help you condense information, but it is always worth asking yourself if a reader will be able to follow easily. If there is any doubt, simplify your sentence, and maybe separate it into two or more sentences.

2. Compound sentences

A compound sentence is made up of two main clauses linked together with words such as and, but, or or. Compound sentences allow you to combine information and ideas:

(8) [The results will contribute to a better control theoretic understanding of heterogeneity in networked systems] and [will be an important tool for the controller synthesis in large-scale robotics].

It is not always necessary to repeat the subject in the second sentence if, as in the above example, it is the same as the subject in the first clause.

3. Complex sentences

A complex sentence is made up of a main clause and a subordinate clause (a clause dependent in some way on the main clause). Complex sentences allow you to combine ideas and signal how they are linked. The two clauses of a complex sentence can come in any order; it depends on the focus of the sentence. In English, sentences often have ‘end focus’, where new or important information is placed at the end of a sentence. In the sentence below, the subordinate clause, introduced by whereas, is first, and the main clause is second and thus more prominent:

(9) Whereas [in the past the focus was on the control of a particular robot,] [modern systems comprise several independent entities which must cooperatively solve tasks together].

Subordinate clauses also include other structures such as:

  • to-infinitive structures

(10) Water is added to dilute the acid.

  • that-clauses

(11) The First Law of thermodynamics asserts that the total energy of the universe is constant and cannot be changed.

  • participle clauses (with present participle -ing or past participle -ed)

(12) The brain is a very complex structure, consisting of around one hundred thousand million (i.e. 1011) neurons.

(13) Published in 1859, On the origin of species is considered to be the foundation of evolutionary science.

  • relative clauses with that, which, who etc.

(14) A heavy metal is one that has a high relative atomic mass.

(15) Heavy metals, which include copper, lead, and zinc, can be a cause of environmental pollution.

Read more about relative clauses here .

Words which are often used to introduce subordinate clauses

Indicating time, duration or sequence: when; while; as; as soon as; since; until; before; after

Stating conditions: if; unless; in case; provided that

Giving reasons: because; since; as

Indicating result: so; so that

Contrasting: while; whilst; whereas

Indicating concession (allowing for something): although; even though

Read more about subordinators in the section on linking words .

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Innehållsansvarig:Susanna Zeitler Lyne
Tillhör: Institutionen för lärande
Senast ändrad: 2023-06-21