Using Articles: A and An In English, we use 'a' before words with consonant sounds and 'an' before words with vowel sounds. However, there are some exceptions. For example, we say 'a university' because the pronunciation starts with a consonant sound ('y'). We also use 'an x-ray' because even though it starts with a vowel letter ('x'), the pronunciation begins with a consonant sound.
'The': Specificity and Exceptions 'The' is used when referring to something specific or known by both the speaker and listener. It is also used when mentioning something for the second time or using superlatives (e.g., coffee is the best drink). Additionally, we use 'the' for groups of society (e.g., the rich) as well as singular objects like mountains (e.g., The Alps), rivers (e.g., The Thames), instruments (e.g., play the piano), morning/afternoon/evening times but not at night.