This document provides guidelines for using "a" versus "an" before words in the English language. It states that "an" should be used before words that start with a vowel sound (a, e, i, o, u), while "a" should be used before words that start with a consonant sound. It then provides examples of applying these rules for various nouns that start with different letters or sounds.

1. a an

2. a use before a word
that starts with
consonant letter

3. an use before a word
that starts with a
vowel letter (a, e, i,
o, u)

4. apple
an

5. apples

6. book
a

7. 1
an a

8. an
apple

9. apples

10. books

11. a book

12. oranges

13. an orange

14. an ice
cream

15. a dog

16. dogs

17. a fish

18. fishes