The definite article in English

As you all (may) know, in English we have two types of articles-definite and indefinite. Their very meaning offers us very useful information for better understanding their role.

The definite article -the

This article displays one of the features of the English language, which is it very simplified form. In Romance languages (French,Spanish,Italian,Portuguese) the definite article changes according to the gender (masculine/feminine) and number (singular/plural).
In English, nouns do not have the category of gender (English nouns are not masculine/feminine) so the article does not need different forms for masculine/feminine.
Even better, it does not even change in the plural.

Let's take some examples:

The boy is tall.
The boys are tall.
The girl is tall.
The girls are tall.

What you do need to know is that the article the has two pronunciations: the /thuh/ before a consonant and the /thee/ before a vowel (a,e,i,o,u)
for example: the /thuh/ dog
the /thee/ orange

When do we use the definite article? 

A first clue is given by the name- it is a definite article which means that it refers to a definite , known, limited category of people/objects etc
When we say : The boy is tall - this means that 'boy' is a known category (I know the person about whom I am talking )

We use the definite article to refer to a category in particular,to individualize a person or an object,an idea.

1.We add the definite article when we are talking about unique elements/objects such as:
the sun,the moon,the earth,the universe
There are not so many unique elements or concepts so maybe you should learn these few.

2.Common nouns can be used with or without the article,depending on the context.
The boys in my class are tall-I refer to a specific category.
Boys are generally tall.- I refer to a general category,all the boys have the same characteristic (that of being tall)

The cat I bought for Christmas is adorable -one in particular.
The cats I saw in the shop were adorable -a category in particular
Cats are adorable -the entire category

I go to school every day. -here we don't refer to a school in particular,but to 'that place everyone knows,which we call school'
The school is  very close to my house- here we refer to a particular school,where I go every day.

This rule applies to all common nouns.
There are,of course some exceptions such as :television, breakfast,lunch,dinner,supper.
We say :
I am watching television.
I am having breakfast.

3. Abstract nouns are used generally without an article:

• nouns showing characteristics:

Beauty is a characteristic of all women.
Greed destroys human relations.
Wisdom is an amazing gift.

 If we refer to a particular beauty,greed or wisdom, we say:
The beauty of this landscape is breath-taking.
The greed of this country will lead to war.
I believe in the wisdom of the ancient  stories.

• nouns representing abstract concepts,ideas:truth,freedom,justice,patience.

Truth is  a remarkable human value.
I love telling the truth.

We are fighting for freedom.
The freedom of speech is guaranteed in our society.

4. Nouns referring to national groups are used with an article:

The Spanish / the British are lovely people-in which case we refer to the Spanish people,nation.

5.We do not use articles with names of :

• continents
• countries

Exceptions: the Czech Republic, the United States of America, the Netherlands, the United Kingdom,

• islands

Exceptions:  when we are talking about a group of islands the Bahamas, the British Isles, the Canaries
cities

• mountains 

Exceptions: The Rocky Mountains, the Alps

• lakes-Lake Ontario

6. Seas,rivers,oceans have the articles