1. ARTICLES Where to use 'a' or 'an'? The choice between 'a' or 'an' is determined by sound. a. The article 'a' is used before a countable noun that begins with a consonant sound. Examples: a donkey, a monkey, a ruler, a woman, a yard, a hole, a university, a union, a European, a ewe, a useful person, a unicorn, a B.A. etc. ๐Because the words such as university, union, European, ewe, useful, unicorn, etc. begin with a consonant sound, i.e. /j/ 'o', we use the article 'a' before all these words. ๐Likewise, we say: a one-rupee note, a one-eyed person, a one-man show, etc. Note: You can notice that in the above phrases 'one' begins with a consonant sound, i.e. /w/. Therefore, we should always use the article 'a' before one. b. The article 'an' is used before a countable noun that starts with a vowel sound. For example, an orange, an apple, an ink-pot, an ass, an enemy, an umbrella, an hour, an hone...