“A/An” is used in front of singular countable nouns ( a person, animal or thing ) which are not specific.

• Yes

• No

We don’t use “a/an” before uncountable or plural nouns.

• No

• Yes

If a noun starts with a consonant sound (b, c, d, f, g, h, j, k, etc.), “a” comes before the noun.

• Yes

• No

If the noun starts with a vowel sound (a, e, i, o, u), “an” comes before the noun.

• No

• Yes

We use ‘the’ in front of all nouns ( It does not matter whether the nouns are singular, plural countable or uncountable ) to describe someone or something specific or unique.

• No

• Yes

It is used in front of nouns which we mentioned before

• A/An

• The

It is used in front of nouns that are only one in the nature like sun, moon, earth, etc.

• The

• A/An

THE is used in front of geographic nouns ( like rivers, oceans, seas, deserts, forests, coasts, swamps,  etc.) except from individual lakes, islands and mountains)

• Yes

• No

It is used in front of musical instruments, cultural institutions and inventions like violin, piano, opera, radio, etc.

• A/An

• The

THE is used in front of countries, cities, towns, states and streets

• Yes

• No