“A,” “an,” and “the” are articles in English, and their usage depends on whether the noun they accompany is specific or nonspecific. Here’s a brief explanation of how to use them:

1. “A” and “An” (indefinite articles):

• “A” is used before words that start with a consonant sound. For example, “a cat,” “a dog.”
• “An” is used before words that start with a vowel sound. For example, “an apple,” “an hour.” These articles are used when you are referring to a non-specific item or thing. They indicate that you are not talking about a particular or specific item, but rather any item of that type.

1. “The” (definite article):

• “The” is used when you are referring to a specific item or thing that both the speaker and the listener are familiar with or can identify.
• It can also be used when you want to make a general reference to a whole class of things, like “The cat is a common pet.” “The” is used to specify a particular item among others or to indicate that the item being referred to is already known or has been previously mentioned.

Here are some examples to illustrate the usage:

• “I saw a dog in the park.” (referring to any dog, not a specific one)
• “I saw the dog that bit me last week.” (referring to a specific dog)
• “She ate an apple for a snack.” (referring to any apple)
• “I picked the apple from the tree.” (referring to a specific apple)

Remember that the choice between “a” and “an” depends on the sound at the beginning of the following word, not its spelling. For example, you say “an hour” because “hour” starts with a vowel sound, even though it’s spelled with an “h.”