1. a/an
1.1. singular countable nouns
1.1.1. Countable noun
1.1.1.1. has both a plural and singular form
1.1.1.1.1. Camera. 2 cameras...
1.2. generic
1.2.1. I do not own a clock
1.2.1.1. It could be any clock
1.2.2. He would like to go to a catholic school
1.2.2.1. any school, as long as it is catholic
1.3. A
1.3.1. noun begins with consonant
1.3.1.1. a book
1.3.1.2. a dolar
1.4. An
1.4.1. noun begins with vowel
1.4.1.1. an ID
2. ?
2.1. determiners/noun markers
2.2. specify if the noun is general or specific in its reference
3. Phrases and idiomatic espressions
3.1. Phrases
3.1.1. Article usage is not predictable
3.1.1.1. Destinations
3.1.1.1.1. Go to work
3.1.1.2. Locations
3.1.1.2.1. In the trash
3.1.1.3. Parts of the day
3.1.1.3.1. At night
3.1.1.4. Chores
3.1.1.4.1. Mow the lawn
3.2. Idiomatic Expressions
3.2.1. informal language
3.2.2. meaning different from the meaning of the words in the expression
3.2.2.1. Beat around the bush
3.2.2.1.1. Avoid saying what you mean, usually because it is uncomfortable
3.2.2.2. Call it a day
3.2.2.2.1. Stop working on something
3.2.2.3. Under the weather
3.2.2.3.1. Sick
3.2.2.4. Hit the sack
3.2.2.4.1. Go to sleep
3.2.3. must be memorized
4. The
4.1. Both singular and plural nouns
4.2. Both countable and uncountable
4.2.1. Uncountable
4.2.1.1. Cannot be counted. No plural form
4.2.1.1.1. Money
4.3. Proper nouns
4.3.1. Name of person, place, institution
4.3.1.1. Capital letter
4.3.1.1.1. Lincoln Memorial
4.4. Specific
4.4.1. The movie I saw was great
4.4.1.1. A specific movie
4.4.2. The time has come for us to fight
4.4.2.1. Time is an uncoutable noun
4.4.3. Unique
4.4.3.1. The sun shines bright
4.4.3.1.1. There is only one sun
4.4.3.2. The Earth moves around the moon
4.4.3.2.1. There is only one Earth
4.4.4. Use THE with superlative adejectives
4.4.4.1. She is the one I love the most
4.4.5. A noun has been mentioned prevoiusly
4.4.5.1. I saw a good movie. The movie was about aliens.