Grammar Focus: Articles ('a', 'an', 'the')

Articles define a noun as specific or unspecific.

• 'a' / 'an' (indefinite): used before singular, countable nouns that are general or not specific. Use 'a' before a consonant sound (a book), 'an' before a vowel sound (an apple).
• 'the' (definite): used before nouns that are specific or already mentioned, or when there is only one of something (the sun, the book on the table).

When no article is needed, we use X (no article) — for example with most uncountable nouns spoken about in general (X coffee, X water).