It can often be confusing to figure out when to use 'a' and when to use 'the.' The most important rule is that you should use definite articles when both you and the person you are speaking to know the specific noun you are talking about.

Previously Mentioned

In the previous lesson, you learned about indefinite articles. Indefinite articles are often used to introduce nouns when they are first mentioned. Definite articles can be used to elaborate on these nouns.

Indefinite Article Definite Article
I got into a fight with a girl in my class. The girl had been trying to steal something from my locker!
Manuela walked into a cafe. The cafe was quiet and peaceful.
We want to buy (♦) shoes and a dress. The shoes have to be black to match our jewellery.

Note that we can also use synonyms or pronouns to replace the indefinite article. Although there is no definite article in the second sentence, it is still specific.

Indefinite Article Definite Article
I got into a fight with a girl in my class. She had been trying to steal something from my locker!
Manuela walked into a cafe. The coffee shop was quiet and peaceful.
We want to buy (♦) shoes and a dress. They both have to be black to match our jewellery.

Can be Seen, Heard or Identified

Sometimes, we use definite nouns because we are talking about something that we can easily see, hear or identify.

The woman picking up Greg is his grandmother. You can both see her so you both know who she is.
Can you lock the door when you leave? You both obviously know which door you're talking about.
The construction on Pine Ave. is finally finished. You have both seen and known of the construction before.

General Knowledge

Often, we can assume that the identity or presense of the noun is generally known. This means that you don't have to introduce the fact that the noun exists. In these cases, we can use definite nouns.

We walked into the movie theatre. The seats were red and gold. It is obvious that there are seats in the theatre, so you both know which seats you are talking about.
I went to watch a play last night. The actors were outstanding. It is obvious that there were actors in the play, so you both know which actors you are talking about.
My car broke down yesterday. The engine wasn't working. It is obvious that a car has an engine, so you both know which engine you are talking about.

Specific Shared Knowledge

Sometimes, the knowledge is not necessarily general knowledge, in that most people might not know about it. However, it might be something that you and the person you are talking to obviously know. If you refer to something and your listener does not have to ask 'which one?' then it is okay to use the definite article.

The Principal wants to talk to you. You both know who the Principal is.
Can you please get me the hammer? You both know which hammer you are talking about, because it's a specific hammer.
We'll have to have a meeting at the club house later. You both know which club house it is, because you go there often.

Familiar Nouns

There are some names of people, places and things that are easily understood.

Some examples of familiar nouns include:

  • the doctor
  • the office
  • the television
  • the airport
  • the supermarket
  • the government
  • the bathroom
  • the park

When you refer to these familiar nouns, the person you are talking to might not know exactly which airport or office you are talking about, but they understand what the idea is.

I had an intense work out at the gym yesterday. You both know what a gym is.
You look terrible! You should go see the doctor. You both know what a doctor is.
I heard a great new song on the radio. You both know what a radio is.

Unique Nouns

Sometimes we use definite articles because the nouns are unique. That is, there is only one.

Some examples of unique nouns include:

  • the environment
  • the beginning
  • the earth
  • the ground
  • the rest
  • the bottom
  • the sun
  • the middle

Superlatives and numbers can also make a normal noun unique.

  • the first step
  • the cleanest plate
  • the second street
  • the tallest tree

Because these nouns are unique, you can use definite articles. Both you and the person you are talking to know what you are referring to.

Put it at the bottom of the staircase. There is only one bottom.
Grab the biggest bag you can find. There is only one biggest bag.
Read until the end of the page. There is only one end.

Exercise

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Exercises

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