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2.  Two forms: A/An
 (A) when a word starts with a consonant
 (An) when a word starts with a vowel.
 Exceptions:
 when a word starts with a silent ‘h’
 with abbreviations, when the first letter is pronounced with a vowel,
like ‘an RAF officer’ RAF = /ɑ: eɪ ef/
 with an ‘h’ that is pronounced weakly and in an unstressed syllable,
like‘a(n) hotel’ and ‘a(n) historian’.

3.  Before occupation, profession, religion, title,
nationality or another state in life
 Exceptions:
 When the occupation can be held by only one person at a time
 when two qualities of the same person are contrasted
 after the post of, the office of, and the rank of.
 Examples:
 He is president of the U.S.A
 Shakespeare as poet and author
 He was offered the the rank of major

4.  NOT before ‘part of’
 Examples:
 During part of the day
 Part of the truth
 Part of the river
 Not after ‘what’ before non-count nouns and
plural nouns
 Examples:
 What beautiful music
 What nonsense
 What beautiful paintings