Sentences: simple and compound

Introduction

In brief: In English there are four basic sentence 'types'. If you are familiar with the patterns of construction on which these four types are based, you can feel confident of expressing your ideas clearly to others. Also, by varying the sentence types that you use in your essays and reports, at university and in the workplace, you can provide your readers with variety and maintain their interest.

The four types of English sentences are simple,
                                                         compound,
                                                         complex, and
                                                         compound-complex.

In this module we will focus on simple and compound structures.

Once you have completed this module, we suggest that you progress to the one titled Sentences: complex and compound-complex. If you do this you will have a complete overview of the four types.

We begin with a description of simple sentences because they are the most basic. Once you understand the fundamentals of simple sentences you can then, when appropriate, adapt your writing to form more elaborate structures. After simple sentences, we examine compound sentences. Compound sentences are formed by linking simple sentences. Consider these examples:

Example 1	Fossil fuels are non-renewable.	(simple sentence)
Example 1	We need to find alternative energy sources.	(simple sentence)

Example 2	Fossil fuels are non-renewable, so	(compound sentence)
Example 2	we need to find alternative energy sources.

In this module you will learn about:

	the structure of a simple sentence,
	the structure of a compound sentence,
	the three ways in which simple sentences may be linked to form compound sentences.

Simple sentences

Definition and description

A simple sentence is a single independent clause. An independent clause is a group of words that together express one complete thought. It includes a subject or subject group and a verb or verb group.

The subject is the person or thing 'performing' the action:

Example	This report outlines alternative energy sources.	(This report = subject)

The verb is the action word.

Example	This report outlines alternative energy sources.	(outlines = verb)

Most verbs describe actions: outlines, describes, reduces and so on.

Sometimes, however, the verb describes a state of being or having, rather than an action: is, was, may be, have, has and so on.

Example	Water is one of the safest energy sources.	(is = verb)

Self-check 1

Do the following express a complete idea, and so are simple sentences, or are they incomplete and therefore not simple sentences? We have included capital letters and full stops in every example to make the task suitably challenging.

	Sentences	Simple or incomplete?
1.	A barometer measures air pressure.	simple incomplete
2.	Because of the rising temperatures.	simple incomplete
3.	Consumption rates rise significantly every year.	simple incomplete
4.	And weight as well.	simple incomplete
5.	Will be assumed.	simple incomplete
Total score /5

Self-check 2

Write the subject and verb of each sentence in the appropriate column. We have designed this exercise to introduce you the idea that a sentence's subject may be a single word or a group of words, and similarly, its verb may be a single word or a group of words. Further explanation of this follows the self check. The exercise is designed to start you thinking!

	Sentence	Subject	Verb	Subject Correct?	Verb Correct?
1.	We waste energy in our daily activities.
2.	Fossil fuels are non-renewable.
3.	The report describes the advantages of solar power.
4.	Australia depends on brown coal for electricity production.
5.	The focus is on the design of a low energy house.
Total score /5

A subject may be a single word or a group of words:

Example	Water is a safe energy source.
	Energy from water is a safe power source.
	Water, wind and solar power are all alternative energy sources to fossil fuels.

Self-check 3

Click on the appropriate words to underline the subject in each sentence.

	Sentences
1.	Solar efficient design reduces fuel bills.
2.	Some scientists support the use of nuclear power as a source of electricity.
3.	Many environmentalists and scientists oppose its use.
4.	The use of wind energy is increasing as fossil fuels become expensive.
5.	Many people have already turned to renewable energy sources.

A verb may be a single word or a group of words:

Example	Some scientists oppose the use of nuclear power.
	The use of wind energy is increasing.
	Many people have already turned to renewable energy sources.

Self-check 4

Click on the appropriate words to underline the verb or verb group in each sentence.

	Sentences
1.	The report describes temporary buildings.
2.	Throughout history, solar energy has provided most of the world's power.
3.	Fossil fuels have become expensive.
4.	In some countries, people are now turning to wind and solar power.

A simple sentence may include two or more verbs or verb groups linked to one subject:

Example	Scientists are monitoring global warming and reporting on its impact.

Self-check 5

Click on the appropriate words to underline the verbs in each sentence.

	Sentences
1.	The powerlines sagged in the freezing conditions and brought down the poles.
2.	Global warming will cause changes to the world's climate systems and will affect sea levels.
3.	The Port Authority will issue warnings and be on standby during the storm.

Bringing your learning, so far, together

Self-check 6

Write the subject/s and verb/s in the appropriate boxes below each sentence.

Note that in the simple sentences you have just studied the word and is used in two different ways:

A. to join pairs of words.

Example	The location and design of windows need careful consideration.

B. to mark the final item on a list.

Example	Insulation in walls, roof and floor will slow down the natural movement of air.

Self-check 7

Decide on the function of 'and' in each sentence and select A ( joins pairs of words) or B (marks final item in a list) in the centre column.

	Sentences	A or B?
1.	Glass roofs and skylights should be carefully designed.	A B
2.	Landscaping, ventilation and insulation all reduce fuel bills.	A B
3.	Wind, water and solar power are all alternative energy sources.	A B
4.	Doors and windows control the flow of air.	A B
5.	Skylights minimise heat loss in winter and heat gain in summer.	A B
6.	The choice of insulation is based on installed cost, fuel cost and severity of climate.	A B
7.	Living areas and children's rooms benefit most from northern exposure.	A B
8.	Heat absorbing and heat reflecting glass both reduce light.	A B
9.	Fossil fuels such as coal, oil and gas are now running out.	A B
10.	Careful orientation of the house will contribute to its visual appeal and reduce fuel bills.	A B
Total score /10

In the next section of this module, Compound Sentences, you will learn a third use of and, but before that, we will review the main points so far and introduce you to some relevant grammatical terms that help us to describe sentence construction. We will also consider a short example of technical writing.

Bringing it together so far

A simple sentence has one independent clause that conveys one main idea. Its subject and verb may be a single word or a group of words.

If a word group comprises the subject, it is called a compound subject.
if a word group comprises the verb, it is called a compound verb.

Example 1	They oppose the use of nuclear power.

Here we have a single subject - single verb construction (they - oppose).
Often grammar texts describe this in an abbreviated way as an s - v pattern.

Example 2	Some scientists and environmentalists oppose the use of nuclear power.

Here we have a compound subject - single verb construction (Some scientists and environmentalists - oppose).
(pattern: ss - v)

Example 3	Some scientists oppose the use of nuclear power and promote alternative energy sources.

This is a single subject - compound verb construction (Some scientists - oppose ... promote).
(pattern: s - vv)

Language in context: simple sentences

The independent clause, with its subject-verb pattern (which may be s - v, ss -v, s -vv or ss - vv), is said to be the basic building block of sentence structure. Practising applying this structure initially to your writing can be a useful step towards clear and effective writing for academic and professional purposes.

Below is an extract from a report. Look closely at the sentences. They are all simple sentences constructed using the various patterns described above.

Simple sentences in a report	Comments
Good ventilation will remove the heat from a house and will reduce air-conditioning costs. Doors and windows directly control the flow of air, through the home. Their location and design need careful consideration. Ventilation is influenced by the type of opening sash on the windows and the direction of the evening wind.	Note how and is used to join pairs of words. These words may be subjects or verbs. Note, also, that a passage composed of a series of simple sentences may lack connecting links. The relationship between each sentence is not shown; it is implied.

Self-check 8

Imagine that you have been asked to proof-read an other student's work to find instances of incomplete sentences. Carefully read the following paragraph and indicate the sentences that you believe are fragments by clicking on any word in the problem 'sentence'. This will underline the whole 'sentence' in black. You can then check your answers. The fragments will be indicated by red underlining.

Johnston et al. (1995) describe solar energy as the most effective and environmentally sound energy source available. But often neglected, even by very experienced designers and builders. Home construction provides a good example to support the point made in the literature. Builders can take advantage of solar power potential by applying three basic principles; sophisticated technologies are not necessarily required. Which is most useful. These three principles are to orient the house with a long axis running east-west, install large north-facing windows, and incorporate wide eaves.

go to page 2