Determiners Questions Medium
We should use the indefinite article 'a' before words that begin with a consonant sound, and 'an' before words that begin with a vowel sound. The choice between 'a' and 'an' is determined by the sound of the following word, not necessarily the actual letter it starts with. For example, we say "a cat" because the word "cat" starts with a consonant sound, and we say "an hour" because the word "hour" starts with a vowel sound.