(a) Before a common noun used in its widest sense, as;
Man is mortal.
What kind of flower is it?
(b) Before names of materials, as;
Gold is a precious metal.
Cotton grows in India, America and Egypt.
(c) Usually before proper noun, as;
China is a modern country.
Jakarta is the capital of Indonesia, not Bali.
Notice that when the article is used before proper noun, they become common nouns, as;
This man is a second Newton.
(d) Before Abstract noun used in a general sense, as;
Wisdom is the gift of heaven.
Notice that an abstract noun, when iti is qualified by an adjective or an adjectival phrase or clause, may have the article, as;
The wisdom of Solomon is famous.
(e) Before a name of Language, as;
We are studying English.
(f) Before the words like, school, college, bed, table, prison, market, etc. When these places are visited or used for their primary purpose, as;
I learnt English at school.
Notice that /The/ is used with these words when we prefer to them as a definite place, building or object rather than to the normal activity that goes on there, as;
The school is very near my home.
(g) Before names of relation, like father, aunt, uncle, etc.
Father has gone to Borobudur temple now.
(h) Before predicative nouns denoting a unique position, i.e. a position that is normally held at one time by one person only, as;
He was elected President of Indonesia.
(i) In certain phrases consisting of a preposition followed by its object, as;
on foot, etc
(j) In certain phrases consisting a transitive verb followed by its object, as;
to catch fire,
to send word,
to lost heart
to leave home, etc.