In earlier articles I covered some of the more common mistakes made by Hong Kong People who learn English as a second language. These included preposition use, countable nouns and so on. This article is about common mistakes caused by using the wrong word and I am specifically covering grammar words. (Yes, grammar word is not an official term, but I am trying to keep things simple.) These words sound the same, the spelling is similar, but they have different uses.
Your shows that you own or are associated with a thing. You're is a contraction for you are. Contractions are most often verbal, but can also be written.
Your handwriting is very good.
You're the strongest boy in class.
There, Their, They're
There is a word indicating a place other than here. Their shows ownership by or association with a group of people. (Or less commonly ownership by a single person of unspecified sex.) They're is a contraction for they are.
The air is cooler over there under the trees.
Their class got to watch an English film.
Than is used to compare different things. Then has several grammatical uses. 1. The most common use of then is to refer to a time or place in a sequence. 2. Then is also used for "as a result". 3. Then is also used as a marker for getting someone's attention. 4. Then is used at the end of a discussion to show agreement.
She is smarter than him.
1. We did not have air conditioning in schools back then.
First we let the cake cool, then we put frosting on it.
2. If he will not do his homework, then he will fail the test.
3. OK then we are ready to start.
4. All right then, we will meet after class for basketball.
It's is a contraction for it is or it has. In English people usually use 's to show possession. However since doing this to the word it would be the same spelling and punctuation as the contraction we don't use the possessive 's with it. Its is something that is owned by or associated with the thing indicated by the term "it". One hint with its, an earlier sentence should show what "it" refers to.
It's warm in this classroom.
We've missed the bus; it's just gone.
I am fixing my computer. That is its hard-drive.
Affect is a verb meaning to do something to something or someone. Effect is a noun that is most often the result of the affecting incident. (Affect is also used for behaving in a way that seems false, or to be a deliberate pose. This use is formal and less common.)
Not learning English can affect how much money you make.
The car will affect you if you get hit crossing the road.
The effect of not learning English is less money in your paycheque.
The effect of being hit by the car was death.
(He affected a smile and talked nicely to the boy he disliked.)
These mistakes are common in Hong Kong; they are also common among less educated native speakers. Second language learners sometimes learn English incorrectly by following poor examples. So be careful of these words.