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Commonly confused words

Complimentary/complementary

Example: At the start of the course all students receive a complimentary CD-ROM.

‘Complimentary’ means to be given free of charge.

Example: The authors examined home activities that were school-like, complementary to school, or unrelated to school.

‘Complementary’ means to combine well.

Comprise/compose

Example: The Commonwealth comprises 1.7 billion people in nations that were formerly part of Great Britain’s colonial empire. 

‘Comprise’ means to consist of, to be made up of. Do not say ‘comprise of’. If unsure, then use ‘include’ or ‘consist of’ instead.

Example: Indonesia is the world’s largest archipelago and is composed of over 18,000 islands.

‘Compose’ means to make up, to form. It is usually used with ‘of’, and is usually used in the passive form (eg is/are composed of, was/were composed of).

Continual/continuous

Example: Continual interruptions distract students when they are writing. 

‘Continual’ means often repeated.

Example: Among those surveyed the length of continuous periods of employment varied enormously.

‘Continuous’ means uninterrupted/unbroken.

Dependant/dependent

Example: Details have yet to be finalised concerning postgraduate students with dependants. 

‘Dependant’ is a noun which refers to a person who depends on someone else.

Example: The discrepancy between poor independent states and rich dependent states is clear from the difference in per capita income.

‘Dependent’ is an adjective which describes one thing which depends on another.

Discrete/discreet

Example: The commonly held image is that Chad is populated by discrete ethnic groups who live in isolation from each other. 

‘Discrete’ means separate.

Example: The university offers a discreet counselling service to students in an environment that is friendly and informal.

‘Discreet’ means maintaining silence or respecting privacy.

Effect/affect

Example: Global warming affects many different facets of life on Earth. 

‘Affect’ is a verb (‘to affect’).

Example: The main effect of global warming is an increasing global average temperature.

‘Effect’ is a noun and is generally preceded by an article ‘an’ or ‘the’.

(However, ‘effect’ can sometimes be a verb with the meaning of ‘to make something happen’ and commonly accompanies the word ‘change’ eg These same factors effected a change in the ancestral rituals of the Amami islands.)

Imply/infer

Example: The supervisor implied that the student’s standard of writing was not good enough. 

‘Imply’ means to express something indirectly.

Example: It is interesting to note that negatives work both ways: if a cat is not a dog, it can be inferred that a dog is not a cat.

‘Infer’ means to arrive at a conclusion by reasoning from evidence.

Less/fewer

Example: Early parish records in Scotland generally contain less information than those in England. 

‘Less’ is used with uncountable nouns

Example: As a result of these barriers, fewer buildings are as energy efficient as they should be.

‘Fewer’ is used with countable nouns.

Passed/past

Example: When Alexander the Great passed through Bukhara, it was already about 1000 years old. 

‘Passed’ means to move in a particular direction or to a particular place/position. Or it can signify being successful in some kind of test.

Example: In the past, a substantial number of archaeological excavations were staffed by volunteers.

‘Past’ means belonging to an earlier time.

Practice/practise

Example: PhD students need to practise their presentation skills before their viva. 

‘Practise’ is a verb (‘to practise’).

Example: The restrictions imposed on students made the practice of ethnography all but impossible.

‘Practice’ is a noun and is therefore often used after an article ‘an’ or ‘the’, or an adjective.

Principle/principal

Example: One of the principal aims of a lecturer is to provide an environment in which students are helped to ‘learn for themselves’ rather than be taught. 

‘Principal’ is an adjective (describing a noun) which means main or most important. It can also be a noun which means the head of a college or university.

Example: One of the hallmarks of universities is the principle of academic freedom, namely the freedom to engage in research of one’s own choosing and freely to publish one’s findings.

‘Principle’ is a noun which means a basic belief, theory or rule.

Raise/rise

Example: Capital flows as trade barriers are raised and lowered depending on the economic health of the states involved. 

‘Raise’ means to increase/push up. A human agent is needed. It is a transitive verb and someone is doing the action of increasing. When it is used in the passive, as here, the human agent is often not mentioned.

Example: Most commentators agree that the trade deficit will stabilise as import prices rise.

‘Rise’ means to go up/increase. A human agent is not needed. This is an intransitive verb and so it cannot be followed by an indirect object. It cannot be used in the passive form.

Stationary/stationery

Example: Aristotle thought the earth was stationary and that the sun, the moon, the planets, and the stars moved in circular orbits about the earth. 

‘Stationary’ means standing still/not moving.

Example: Overhead transparencies and coloured pens are kept in the departmental stationery cupboard.

‘Stationery’ refers to pens, paper etc.

There/their

Example: The households surveyed operate dozens of non-agricultural businesses on their farms. 

'Their' is used to indicate possession, ie if something belongs to someone or something.

Example: There are a number of variables that may affect the proportion of income earned from agriculture.

'There' is used to indicate the existence of something.

Varying/various

Example: Drawing valid generalisations from research studies conducted under varying conditions is a challenging task. 

‘Varying conditions’ implies the individually changing conditions of the same variable(s).

Example: A further twenty-three projects will be funded from various sources in 2006/2007.

‘Various sources’ implies that the sources are different from each other.

Example: Participation in seminar discussions can be greatly improved by varying both the composition of the student groups and the physical layout of the seminar room.

‘Varying’ can also be a verb.