4.2 Sentence types
4 Sentence structure 1
In English, subject + verb structures occur in three main types of sentence.
Look again at some of the sentences from 4.1.
✵ Which has more than one subject + verb structure?
✵ How are they linked together? What is the relationship between the two parts of the sentence?
1) Bacteria are the smallest living organisms.
2) A motherboard is the major circuit board inside a computer and it holds the processor, the computer bus, the main memory and many other vital components.
3) Although quarantine is the oldest method of dealing with communicable diseases, it is now generally used only for very severe diseases, such as cholera and yellow fever.
The three main sentence types exemplified here are: simple (1) (with only one subject + verb structure), compound (2) and complex (3) (both with two subject + verb structures). These sentence types will be discussed in more detail in the following sections.
4.2.1 Forming simple sentences
Simple sentences consist of a single main clause, i.e. they are built around a single subject + verb structure. As well as containing a subject, and a verb which agrees with the subject, a main clause can also contain:
✵ an object (who or what is affected by the verb), e.g.
∘ The university funded the study.
∘ The group researched the causes of diabetes.
✵ a complement (information about the subject or object of the clause), e.g.
∘ She is a doctor.
∘ They made him head of department.
✵ an adverbial (information about the situation), e.g.
∘ The book has undoubtedly contributed to the debate on climate change.
∘ In the early 20th century, many advances were made in the field of physics.
∘ When conducting trials on mice, they found the drug to be effective and harmless.
Note that subjects, objects and complements are usually nouns, or rather noun phrases (with more than one word). However, some other elements, such as subordinate clauses ( 4.2.2 for an explanation of subordinate clauses), can also take on this function, e.g.
What Darwin did changed the way we understand biology.
Also note from the above examples that adverbs, prepositional phrases and subordinate clauses can function as adverbials.
Explorative Task (i)
Underline extra words or phrases that have been added to the main subject + verb structure in each of the simple sentences below. What is the grammar/function of these words and phrases?
1) Temperatures rose.
2) Temperatures rose steadily.
3) Average temperatures in the south of the country rose steadily.
4) In the period from 2003 to 2013, average temperatures in the south of the country rose steadily.
Explorative Task (ii)
These sentences are not accurately formed. Can you identify the problems with them?
1) It undoubtedly true that computational simulations should not completely replace experimentation.
2) An ICT system is a set-up consists of hardware, software, data, and the people who use these things.
3) Vitamin D is important for the absorption and use of calcium and phosphorus by the body, it is essential for the formation and health of bones, teeth and cartilage.
4.2.2 Compound and complex sentences
As previously mentioned, compound and complex sentences contain two subject + verb structures, i.e. clauses, but combine them in different ways.
Look again at these sentences from 4.1.
✵ In which sentence could the two clauses exist independently?
✵ In which sentence is one clause (which?) dependent on the other?
1) A motherboard is the major circuit board inside a computer and it holds the processor, the computer bus, the main memory and many other vital components.
2) Although quarantine is the oldest method of dealing with communicable diseases, it is now generally used only for very severe diseases, such as cholera and yellow fever.
In 1), two facts are combined, but they are not dependent on each other here. If the sentence were split into two, there would be no change of meaning. They are independent main clauses joined by a coordinating conjunction, and, to form a compound sentence.
In 2), the subordinating conjunction although introduces a dependent subordinate clause, which must be connected to a main clause for the sentence to make sense: the two facts (quarantine is the oldest method; it is not widely used now) are related here to form a complex sentence. If the subordinating element is removed, the link between the facts is not explicit.
A compound-complex sentence contains both coordinated and subordinated clauses, e.g.
Study Box: Avoiding common errors in compound and complex sentences
1) Be careful not to duplicate conjunctions, e.g.
As some of the drug’s side effects may be difficult to detect and patients might take a long time to become aware of them.
As some of the drug’s side effects may be difficult to detect, patients might take a long time to become aware of them.
Some of the drug’s side effects may be difficult to detect and patients might take a long time to become aware of them.
2) Be careful not to write just half a sentence when using subordinating conjunctions such as whereas and because, e.g.
Influenza B and C viruses mainly affect humans. Whereas influenza A viruses infect a range of mammalian and avian species.
Influenza B and C viruses mainly affect humans, whereas influenza A viruses infect a range of mammalian and avian species.
3) Avoid ’stringy’ sentences with lots of ands and buts. They are wordy, unstructured and difficult to read.
The weather conditions worsened and this caused a number of problems and there were forest fires and droughts but the long-term effects were limited.
The weather conditions worsened, which caused a number of problems including forest fires and droughts. However, the long-term effects were limited.
Correct or improve these sentences.
1) Although the structure of the building was weakened, but experts agreed that there was no danger of it collapsing.
2) The drug trial was abandoned. Because the side effects were considered to be too serious.
3) The panda was artificially inseminated and experts claimed that her hormone and behavioural signs indicated that she was carrying a foetus but her behaviour changed and she is thought to have lost the cub.
18.104.22.168 Forming compound sentences
The typical sentence pattern for compound sentences is:
subject + verb (…) + coordinating conjunction (and/but/or) + subject + verb (…)
✵ A motherboard is the major circuit board inside a computer and it holds the processor, the computer bus, the main memory and many other vital components.
A comma is often used before the conjunction, e.g.
✵ Obesity appears to have more negative health consequences than smoking, drinking or poverty, and it also affects more people.
In compound sentences, when both clauses have the same subject, the subject of the second clause can be omitted, e.g.
✵ Glass is resistant to most chemicals but can be dissolved by hydrofluoric acid.
However, it should be retained if there is any chance of ambiguity.
Link the sentence halves with the right coordinating conjunction to form compound sentences.
1) A poor diet can lead to obesity
2) The hurricane destroyed a number of buildings
3) The drug can be taken orally
4) The Internet has improved our lives in many ways
5) Some patients respond well to therapy
a) it has also brought with it a number of problems.
c) others show little improvement.
d) cause a number of health problems.
e) caused major damage to trees.
22.214.171.124 Forming complex sentences with subordinating conjunctions
Typical sentence patterns when using subordinating conjunctions are:
subordinating conjunction + subject + verb (…), + subject + verb (…)
(clauses usually separated by comma)
subject + verb (…) + subordinating conjunction + subject + verb (…)
(comma not usually used)
Some common examples of subordinating conjunctions used in academic writing are:
✵ 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: although; even though
Choose the correct subordinating conjunction.
1) Many people prefer natural remedies to conventional drugs as/while they believe natural remedies have fewer side effects.
2) Because/Whereas many buildings in the city are built to withstand earthquakes, some are still at considerable risk.
3) Although/Since the weather conditions were fairly good, they decided not to proceed with the test flight.
4) Mobile phones should be switched off unless/in case they interfere with emergency equipment.
5) Take the drug as soon as/until the symptoms occur.
Link the sentence halves and insert the correct subordinating conjunction to form complex sentences:
although; while; as; so that; whereas
1) ___ it remains the case that the brain as a whole has limited powers of repair
2) The stability of glass makes disposal difficult
3) The reasons for developing type 1 diabetes have not been identified
4) ___ chemistry reaches down into physics for its explanations
5) It is sometimes necessary to acquire information regarding the cause of a ceramic fracture
a) ___ measures may be taken to reduce the likelihood of future incidents.
b) it reaches upwards into biology for many of its extraordinary applications.
c) ___ some suggest interaction of dietary factors during pregnancy and early neonatal life.
d) the potential use of stem cells offers new hope for future therapy for degenerative brain diseases.
e) ___ it will not readily break down.
4.2.3 Other complex sentences
There are a number of other subordinating mechanisms which are common in academic writing.
126.96.36.199 Participle clauses
Typical sentence patterns using participles are:
subject + verb (…), ——ed/ing (…)
Complete the sentences with one of the verbs below in a suitable form:
prompt; weigh; use; compose
1) The traffic light system is used on the front of packaging to help consumers assess at a glance the fat, saturated fat, sugar and salt content, __________ them to make healthier dietary choices.
2) The brain is a very complex structure, ___________ of around one hundred thousand million (i.e. 1011) neurons.
3) ____________matter before it had undergone transformation from one substance to another led to the principal concept that underlies all explanations in chemistry: the atom.
4) Inexpensive microelectronic circuits are mass produced by ______________ some very ingenious fabrication techniques.
188.8.131.52 Infinitive clauses of purpose
Infinitive clauses of purpose are very common in scientific writing.
Typical sentence patterns are:
subject + verb (…) + infinitive clause
(comma not usually used)
(comma not usually used)
The phrases in order to and so as to can also be used to introduce purpose.
✵ in order to/so as to lower the pH of soil
Link the sentence halves with the right verb to form complex sentences:
1) All structural concrete contains to reduce steel reinforcement in the form of bars or welded mesh
2) We must understand the transmission mechanisms of infection so that we can interfere with those mechanisms
3) Water is then added
4) Stemming from analytical chemistry is forensic chemistry, in which the techniques of analytical chemistry are used for legal purposes
5) Aluminium—lithium alloys have been developed by the aircraft industry
to track down
a) the weight and improve the performance of its aircraft.
b) the low tensile strength of concrete.
c) suspects, and to analyse the scenes of crimes.
d) the acid to 20—30% and the mixture is again heated to 100°C for 1 hour.
e) effective public health measures.
This structure can be very useful in the methods section of a research report, often combined with the passive, e.g.
To obtain the correct values of Ts (skin temperature) by compensating for the effects of different radiation sources the following parameters were supplied for the camera: …
In order to allow acclimatisation, the thermograms were recorded after a 15 min stay in the respective environment.
To document the recurrence of thermal windows, we further partitioned each body part into three sections …
To document the relative size of a thermal window and to observe its chronological development we used the software package ImageJ 1.36B …
To test for the influence of Ta, age, and body weight on Ts, we used linear mixed effect models …
(Weissenbock et al., 2010: 183)
Many verbs (also adjectives and nouns) introduce a subordinate clause with the conjunction that, e.g.
✵ The First Law of thermodynamics asserts that the total energy of the universe is constant and cannot be changed.
It is often possible to omit that from the clause, but it is usually a good idea to retain it in academic writing as it can improve clarity.
Add the word ’that’ to these sentences where necessary/preferable.
1) Immunisation requires we understand the immune mechanisms and we design vaccines that will successfully stimulate protection.
2) One estimate suggests 1.46 billion adults worldwide were overweight in 2008,1 and projections suggest by 2020 over 70% of adults in the United Kingdom and United States will be overweight.
3) It is popularly believed the cells of wood are living cells, but this is certainly not the case.
4) Chemists take a great deal of interest in the rates of chemical reactions as there is little point knowing they can, in principle, generate a substance in a reaction but it would take a millennium to make a milligram.
5) Over time, it is becoming more apparent the earth is virtually a closed system relative to its constituent materials and its resources are finite.
4.2.4 Focus on relative clauses
Relative clauses are very common in academic writing. They are useful in science as they can specify or define a particular object, e.g.
✵ A heavy metal is one that has a high relative atomic mass.
or add information to a statement, e.g.
✵ Heavy metals, which include copper, lead, and zinc, can be a cause of environmental pollution.
They cause difficulty because they are quite complex in terms of grammar and punctuation.
8.4 for examples of relative clauses in definitions
Compare the relative clauses highlighted in the text. In what ways do they differ?
Since the start of the industrial revolution in the late 18th century, there has been an exponential increase in our exploitation of materials for use in the technologies that have driven economic growth and increased the prosperity and living standards in much of the world. These advances have not, of course, been uniformly experienced owing to the wide variation in political, economic and social conditions in different regions and countries. Much of the growth has only been possible with the associated development and fabrication of infrastructure, which has required enormous quantities of construction materials with controlled and reliable properties.
(Domone and Illston, 2010: 535)
Defining or non-defining relative clause?
The first clause is a defining (or ’restrictive’) relative clause. It specifies only those ’technologies’ responsible for these effects; it does not refer to ’technologies’ in general. Defining clauses can begin with that or which (that or who for people).
The second clause is a non-defining/non-restrictive clause. It refers to ’the development and growth of infrastructure’ in general, adding some extra information rather than specifying a certain part of it. Non-defining clauses must begin with which (or who for people), and they must be separated from the main clause by a comma/commas.
Complete the sentences with: that/which/who and, if necessary, a comma/commas.
1) A computer virus is a program ______ can damage your computer.
2) Brisk walking is something ______ many doctors recommend to those ______ are overweight.
3) A marine engineer is someone ______ works with underwater equipment and systems.
4) Vitamin C ______ is also known as ascorbic acid is required by the body for the growth and repair of tissue.
5) Global warming leads to climate change ______ will ultimately affect people all over the world.
Sometimes, the relative pronoun of a defining relative clause can be omitted if it refers to the object, rather than the subject of a sentence. Compare:
✵ technologies that have driven economic growth
✵ technologies (that) industry has employed
Can any of the relative pronouns in the sentences in Practice (i) be omitted?
Relative clauses can also sometimes be further reduced (to form ’reduced relative clauses’), i.e. both the relative pronoun and auxiliary verb to be can be omitted, leaving just a past participle, e.g.
✵ This study shows that neither recipes created by popular television chefs nor ready meals produced by three leading UK supermarket chains meet national or international nutritional standards for a balanced diet.
✵ Highly educated people living in urban areas use more dietary supplements.
Can any of the sentences in Practice (i) be reduced?
Relative clauses with a preposition, sometimes part of a more complex phrase, are also characteristic of formal writing, e.g.
✵ The ancient technique of ’stained glass’, in which pigments were fired directly onto the surface of clear glass, has been updated recently.
✵ Bacteria and their products have been used extensively to control pests such as caterpillars, bollworms, corn borers, and fruit leaf rollers, all of which can damage crops used for food.
✵ The UK manufactures 750,000 tonnes of flat glass each year, three quarters of which goes into glazing products for buildings.
Add the correct preposition to the sentences:
at; of; above; in
1) There are several theories, most ____ which have been discussed at length in the literature.
2) This is the paper ____ which Maxwell’s equations first appeared.
3) The line on the graph indicates the threshold ____ which the reaction is deemed significant.
4) Note the rate ____ which the solution heats up.
5) The plants produced pods, some ____ which were green, and some ____ which were yellow.
In possessive constructions, whose is commonly used with inanimate objects in academic writing: Biber et al. (1999: 618) found that 75% of whose in academic writing referred back to inanimate nouns, e.g.
They realised that only another planet, whose orbit lay beyond those already recognised, could explain the behaviour of the nearer planets.
These constructions can also be written as more complex phrases. Compare:
the orbit of which lay beyond those already recognised
Join these sentences together to form a single sentence containing a relative clause.
1) Arsenic is an extremely toxic substance. It is sometimes used as an insecticide.
2) The Royal Society was founded in 1660. It is a self-governing fellowship of many of the world’s most distinguished scientists.
The Royal Society _______________________
3) The disease has a number of symptoms. Most of them can be controlled through medication.
The disease _____________________________
4) Technology can help countries to develop. It is unclear to what extent.
The extent _____________________________
5) Gravitational wave astronomy is an emerging new field of astronomy. It aims to use gravitational wave detectors to collect observational data about compact objects.
Gravitational wave astronomy _____________
6) A crystal is a piece of matter. Its boundaries are naturally formed plane surfaces.
A crystal ______________________________
7) Tim Berners-Lee invented the Internet. It was in 1989.
It was Tim Berners-Lee ____________________
8) Fracking is a procedure. A solution is pumped into the earth to fracture rock and access oil and gas.
Think about how you could use this technique to produce a simple paraphrase of original sources. Chapter 7