a/an countable noun

a starting with a vowel: unique, university, union, European

an begins with a consonant: hour, honor

The countable noun expresses a type of thing or refers to something in particular.

Generally not used unless specified

The adjective:

The ordinal/adjective superlative: Tourism has become the top earner of foreign currency for many countries since the late twentieth century.

Plural form of word/phrase countable nouns: a few, few, a variety of, various, other, numerous, a number of, different, one of, many, several, these. Example: Smoking cessation is one of the likely factors that contribute to the development of obesity.

Word Countable noun singular: any other, another, each, neither, either. Example: Many teenagers begin smoking habits due to peer pressure but not for any other reason.

Word/phrase Uncountable noun: a little, little, less, much, a large amount of. Example: Little progress has been made towards tackling poverty.

Uncountable nouns do not have a plural form: information, knowledge, evidence, behaviour, news, research, waste, pollution.

irregular plural form

Singular form: he, she, it, one, anybody, everybody, somebody, nobody

Plural form: they