I read a gramar book involve "a an the". Before the last sentense I thought understand it.

a an are used to refer to a thing of the group for example : I've got a car (There are many car and I've got one )

the is used to refer to the only one for example : I'm going to clean the car ( my car only one car)

The last sentense is compare a and the I don't get ---> I bought a jecket and a shirt. The jacket was cheap. but the shirt was expensive

Why it doesn't use I bought the jecket and the shirt .

Originally Posted by mooyong
I read a gramar book involve "a an the". Before the last sentense I thought understand it.

a an are used to refer to a thing of the group for example : I've got a car (There are many car and I've got one )
Here, you are just saying, you have a car, but do not know, which one it is or how it looks or the model.

the is used to refer to the only one for example : I'm going to clean the car ( my car only one car)
Here, you know, which car you are talking about.

The last sentense is compare a and the I don't get ---> I bought a jeacket and a shirt. The jacket was cheap. but the shirt was expensive

Why it doesn't use I bought the jeacket and the shirt .
Ex 1:

John: Hi Ron, what did you buy for me from Paris?
Ron: I bought a jacket and a shirt for you.

Ex 2:

John: Hi Ron, please buy for me a jacket, shirt and a pair of shoes while you are coming.
Ron: Ok, I will.
Ron: I bought the Jacket and the shirt, but I did not buy shoes. I ran out of time.

===Not a teacher===

Here are the rules for when to use "A, An or The":
• a = indefinite article (not a specific object, one of a number of the same objects) with consonants
She has a dog.
I work in a factory.
• an = indefinite article (not a specific object, one of a number of the same objects) with vowels (a,e,i,o,u)
Can I have an apple?
She is an English teacher.
• the = definite article (a specific object that both the person speaking and the listener know)
The car over there is fast.
The teacher is very good, isn't he?
• The first time you speak of something use "a or an", the next time you repeat that object use "the".
I live in a house. The house is quite old and has four bedrooms.
I ate in a Chinese restaurant. The restaurant was very good.
• DO NOT use an article with countries, states, counties or provinces, lakes and mountains except when the country is a collection of states such as "The United States".
He lives in Washington near Mount Rainier.
They live in northern British Columbia.
• Use an article with bodies of water, oceans and seas -
My country borders on the Pacific Ocean
• DO NOT use an article when you are speaking about things in general
I like Russian tea.
• DO NOT use an article when you are speaking about meals, places, and transport
He has breakfast at home.
I go to university.
He comes to work by taxi.
Check your knowledge of 'a', 'an' or 'the' with this definite and indefinite article review quiz

Hi.

A and An are indefinite article.(usually use to refer to noun in general)
The is definite article.(usually use to refer to a specific noun)

The most common usage of A, An and The is:

" I have a car.The car is red."

For the first time you mention about a singular noun, (in this case is "car"), you must you "a". For the second time or more, when you want to mention about the same noun, you cannot use "a" again. You must use "the" because you are referring to a specific car which is your car and your car is red.