C. A Definite Article 'the' is a determiner and used in front of a noun that introduces a noun phrase and implies to one particular thing (specific), or is common knowledge, or is about to be defined. (e.g. the book on the table). The definite article can be used with singular, plural, or uncountable nouns. Compare with indefinite article.
1. to introduces a noun phrase and implies that the thing has already been mentioned (e.g. When we were on holidays, we stayed at a hotel. Sometimes we ate at the hotel and sometimes we went to a restaurant.)
2. common knowledge (e.g. Life can be very hard for the lazy people. The art is long, life is short, opportunity fleeting, experiment dangerous, judgment difficult.)
3. thinking of a specific thing (e.g. Hundreds of people have complained to the company about new politics.)
4. know exactly what we are referring to. (e.g. I am going to the church. (our church))

C1. Use the Definite Article 'the'
1. only one: the world, the earth, the sun, the sky, the sea, the ground, the country, the end of this month, but space (e.g. the Earth rotates, it also moves, or revolves, around the Sun.)
2. only one in specific place or in those surroundings. (e.g. We live in a small village next to the church. (= the church in our village))
3. already mentioned it. (e.g. When we were on holidays, we stayed at a hotel. Sometimes we ate at the hotel and sometimes we went to a restaurant.)
4. to say something about all the things referred to by a noun (e.g. The wolf is not really a dangerous animal. (= Wolves are not really dangerous animals.))
5. with adjective (without noun, always plural in meaning): the blind, the dead, the deaf, the disable, the elderly, the homeless, the injured, the old, the poor, the rich, the sick, the unemployed to talk about groups of people, the young, etc. (e.g. She works for a group to help the disabled.)
6. with a superlative adjective (e.g. It is the oldest building in the town.)
7. use 'the' before 'same' (the same) (e.g. Your pullover is the same colour as mine.)
8. (go to) the cinema, the theatre and the radio (e.g. Ann goes to the cinema a lot, but she hasn't been to the theatre), but television.
9. to talk about musical Instruments (e.g. Ann plays the piano very well.)
10. to refer to a system or services. (e.g. How long does it take on the train?)
11. Countries whose names include words like kingdom, states, republic, plural nouns in their names. (e.g. the United Kingdom; the People’s Republic of China; the Netherlands) The + Nationality: the English (the people of country), but an Englishman
12. Geographical features, such as mountain ranges, groups of islands, rivers, seas, oceans and canals. (e.g. the Himalayas; the Canaries; the Atlantic Ocean; the Amazon; the Panama Canal) Directions: the north and the Far East, but northern Korea
13. Organisations (e.g. the United Nations), and most newspapers (e.g. The Times; The Washington Post)
14. well known buildings or works of art (e.g. the Empire State Building; the Taj Mahal; the Mona Lisa; the Sunflowers), Hotels, pubs and restaurants, except the name of the hotel or restaurant is the name of the owner. (e.g. the Ritz; the Déjà Vu, Brown’s; Brown’s Hotel, etc.), and Most other buildings have name with The (e.g. The Sheraton Hotel, The Palace Theatre, The Guggenheim Museum, The White House)
15. Families: the Obamas (Obama's family)

C2. Do not normally use the Definite Article 'the'
1. to talk about things or people in general: athletics, Chinese food, classical music, crime, doctors, dogs, English, fast car, football, history, life, physics, skiing, stamps, teachers, stamps, etc.
2. thinking of the general idea of places: church, college, hospital, school, university, etc. (e.g. Go to church. vs. Somebody went to the church to repair the roof). Most other places are needed the definite article 'The'
3. in general no 'the': bed, work, home
4. do not normally use 'the' with the names of meals (breakfast, lunch etc.), but a very nice lunch
5. do not use 'the' before noun + number (e.g. page 29 (of a book))
6. go to see/ be at sea, no 'the' when the meaning is 'go/ be on a voyage'
7. Names of most city street: Queens Road
8. Important institutions with two word: Harvard University. (e.g. Buckingham Palace but the Royal Palace (Royal is an adjective but it is not a name))
9. most people, most books, most cars etc.
10. with names: William Shakespeare wrote Hamlet
11. Names of companies, airlines are usually without 'the'