Before a countable singular noun mentioned for the first time E.g: I can see ....nice house in the picture.
A,an
When the object or group of objects is unique or considered to be unique E. g: ...Earth is round.
The
Before HALF when half follows a whole number Eg. :one and ... half
A
Before a noun which is mentioned for the second time Eg. :I can see a tree. ....tree is very tall.
The
As equivalent of one
A, an
Before certain proper names of seas, rivers, groups of islands, chains of mountains, plural names of countries, deserts, regions E.g: ...Alps
The
Before parts of the body E.g: I patted .... his shoulder
Zero article
Before TOWN when we are speaking of the speaker's own town E.g: I will go to....town.
Zero article
Before titles containing OF E.g: .... queen of England
The
Before names of professions
A, an
Before names consisting of noun + of + noun E.g: ....United states of America
The
In expressions of price, speed, ratio, etc. E.g: It costs 50p .... kilo
A, an
Before superlatives and first, second etc.
The
With singular noun it can represent a class of animals or things E.g: ...whale is in danger of extinction.
The
Before SCHOOL, CHURCH, PRISON, HOSPITAL, BED when these places are visited or used for their primary purpose E.g: I go to ..... church every Sunday.
Zero article
Before plural surname it can be used to mean a whole family
The
