Some Spelling Rules:
These are a few of the pairs that are often used wrongly.
Compliment or complement?
A compliment, or a complimentary remark, is something you pay someone when you want to be nice: “What a nice dress!” “That’s very clever”. “You played very well” etc. Sometimes complimentary means ‘free’: e.g. complimentary tickets.
A complement, or a complementary thing, is something that completes something: e.g. a ship’s complement is her crew; her assignment has a complementary guide to experimental techniques; yin is complementary to yang.
Principle or principal?
A principle is an underlying idea, or a moral belief, etc.
A principal is either a Head (e.g. a sort of Head-teacher); or an adjective describing the most important thing, “The principal point in this lecture is…”
Practice or practise?
A practice is a noun – something that you do, “there is a football practice tonight”; “I did 5 hours’ piano practice yesterday”; “my usual practice is to warm up for five minutes first”; “she is in General Practice”. (If you can say “a practice” in your sentence, then it is practice.)
To practise is a verb – to do something, e.g. “I practised my vocabulary last night”; “he practised his speech in front of a mirror.”
Affect or effect?
To affect is a verb – to do something, e.g. “she was affected deeply by the death of her husband”; “to raise taxes affects everyone”.
An effect is a noun – a thing, or result. Cause and effect are opposites. “The effects of the war were…”. Sometimes effects means possessions: “Carry your personal effects with you”.
Lie or lay – or laid?
To lie is an intransitive verb – i.e. it has no object. You lie down.
To lay is a transitive verb – i.e. it has an object. You lay something down.
Confusingly, the past tense of to lie is lay: “She lay down for a moment at three o’clock”. The past tense of to lay is laid: “They laid down their weapons”.
Subject: Some Spelling Rules: 
Mon Aug 11, 2014 4:17 pm
