Теория:

Study some necessary moments for the definite article.
  
1. We use the with the phrase: the same.
 
We live in the same street.
  
Frith_Street_London_on_a_July_morning.jpg
 
2. We use the definite article with these words: the sun/ the moon/ the sky/ the sea/ the country/ the world.
  
The sun is shining today.
  
images.jpg
  
The world is full of different people.
  
3. We use the with: the police, the army, the fire brigade.
 
Let's call the police. The situation is dangerous.
  
скачанные файлы (1).jpg
 
 
4. The definite article is used in these phrases: the top/ the end/ the middle/ the left/ the right/ the bottom.
  
The table is in the middle of the room.
  
5. We say the radio, but television without articles.
 
I listen to the radio a lot.
  
Телевидение-и-радио-в-Сербии.jpg
  
What's on television tonight?
Источники:
phillypolice.com
phillypolice.com
likesuccess.com
en.wikipedia.org