The Definite Article

when something has been​​ mentioned before:

‘Has he got a car?’ ‘Yes.​​ The car​​ he has is expensive.’

with​​ of:

the colour of​​ my skirt

when​​ only one​​ of something exists:

the President, the Pope, the moon, the sky

when referring to​​ groups of people or nationalities:

the rich, the sick, the English, the Russian

when talking about​​ species​​ (in the context of biology):

The lion​​ is​​ a carnivorous animal.

when talking about​​ musical instruments:

I play​​ the guitar. He plays​​ the piano.

with​​ the media:

the press, the news, the radio, the papers, the tv

But:​​ I watch television.

with​​ superlatives​​ and​​ ordinal numbers:

the first, the​​ second, the best, the only, the last

when talking about​​ parts of the body:

He was hurt on​​ the head.

when talking about geographical features:

1. oceans, rivers, mountains:​​ 

2. regions:​​ 

3. groups of islands:​​ 

4. some countries:​​ 

5.​​ other:​​ 

1. the​​ Themes, the Alps, the Pacific

2. the Middle East, the Sahara, the Amazon

3. the Solomon Islands, the Caribbean

4. the USA, the Ukraine, The UK, the United Arab Emirates, the Netherlands

5. the sea, the coast, the hills, the mountains, the countryside

with​​ the​​ dates(only in speech):

the twentieth of July, October the fifth

talking about​​ entertainment:

the cinema, the theatre, the opera, the museum

when referring to​​ hotels and restaurants:

the Hilton, the Grand Hotel, the Oriental

with​​ expressions:

the​​ traffic, in the morning, in the afternoon, the metro, the doctor, the dentist, the hospital, the supermarket, the bank