The document describes a series of images where the reader is asked "What's this?" and the item is identified, with either "a" or "an" being used correctly before the name based on whether the next word starts with a vowel sound or consonant sound. It notes words beginning with vowels use "an" while words beginning with consonants use "a", with an example given of "unicorn" and "unfriendly unicorn" to show the pronunciation is what determines which article to use.