Contribuciones

A/ AN
The correct choice of the “articles” a and an depends on the initial sound of a word, not on the initial letter, of the word thatthey precede.
The letter a should be used before all words beginning with a consonant sound except silent h (an honor) and before wordsbeginning with vowels that represent combined consonant and vowel sounds (university, unit).
Examples: a boy, a European, a j, a picture, a store,a table, a bottle, a window, a phone, a hyphen, and a one-horse town, a computer, a banana, a baby, a mobile phone, a window, a horse, atomato, a potato, a package of cigarette, a cigarette, a ball.
an (AN)
The word an should be used before all vowel sounds (a, e, i, o, u).Examples:
an entry, an f, an hour, an orange, an ape, an odor, an idea, an eagle, an honor, an umbrella, and an unbeliever, an orange, an apple,an assistant, an ipod, an answer, an ant, an elephant, an old bike, an English teacher, an accident, an eye, an elf, an earring, an ankle.The initial consonant h is silent, so the word has an initial vowel sound; hence, an honest man, an hour ago, an heir to the throne, anhonest and an honorable peace;
On the other hand, when a word begins with an aspirated h (a speech sound followed by a puff of breath or thespeech sound represented by English h), correct usage is:
a hotel, a house, a hill, a hymn, a honeycomb, and a history or a historical.