What is the rule for using 'a' or 'an' before words starting with 'g'?
The rule for using 'a' or 'an' before words starting with 'g' is to use 'a' before words starting with a hard 'g' sound (e.g. 'a guitar') and to use 'an' before words starting with a soft 'g' sound (e.g. 'an hour').