Students ask when to use ‘a and ‘an’ in a sentence. The answer is very simple.
A or an is used with a singular noun for example a boy, a book. If a noun begins with a consonant sound, we use a. If a word begins with a vowel sound an is used, for example, an honest man. A and An make the noun or pronoun something un- specific or indefinite. A is used with the singular nouns starting with a consonant and An is used with the word that starts with the vowel. Sometimes a word starts from a consonant but it produces a sound of a vowel so we also use An with that type of word.
Use of A and An :
Indefinite articles are used only with singular nouns. We cannot use the ‘a’ or ‘an’ with the plural nouns. We don’t use indefinite articles with uncountable nouns.
A singular noun is the type of noun that indicates to only one person one place one thing or one idea. So we use indefinite articles with the singular noun, not with the plural noun.
As an example:
A chair, A table, A bag, A book, A cup, An apple, An orange, An egg, An inkpot,
A countable noun is the type of noun that indicates the things that are not countable we cannot count them. So we do not use indefinite articles with uncountable nouns.
When to use A:
We use A with the word that’s initial sounds are pronounced as a consonant.
- A cup
- A pen
- A book
- A bag
Read more about Articles in English grammar
When to use An:
We use An with the word that’s initial sound pronounced as a vowel.
- An apple
- An orange
- An egg