Some students become very confused by two articles "a" and "an".
Most times it is as easy as; a,e,i,o,u. If there is a vowel
present in the noun you are generally told to use "an". However,
there are exceptions. These exceptions are due to "sound-likes".
Examples:  An Hour has the silent H... sounds like "our" A
University becomes a tongue twister if you would use "an" A
European has the "your" sound  Remember these are just examples.