In English there is a little family of words called articles. They are:
a, an, and the
a and an like to point out singular nouns.
a, an --------> singular nouns
the likes to point out singular and plural nouns.
the --------> singular and plural nouns
The article a is seen with words that begin with consonant sounds.
B, C, D, F, G, H, J, K, L, M, N, P, Q, R, S, T, V, W, X, Y, Z
a boy, a house, a letter, a small table, a zoo
The article an likes to be with words that begin with vowel sounds.
A, E, I, O, U
an apple, an egg, an ice cream cone, an open door, an umbrella
Here are some sentences that combine all three articles:
That is a frying pan.
There is an egg in the frying pan.
a and an are used to introduce a singular noun; that is, the first time we use the noun.
the is used when we talk about the introduced noun again.
In the sample sentences we first say a frying pan. The next time we mention it we say the frying pan.
It's pretty easy so far, right? But, remember, this is English so, of course, we have...
Not all nouns that begin with a consonant, begin with a consonant sound. Go with what you hear.
an hour, not a hour
The h is silent so you only hear the vowel sound - o - at the beginning of the word, like
an honest man
Not all nouns that begin with a vowel, begin with a vowel sound. Go with what you hear.
a one-eyed monster, not an one-eyed monster
One begins with a w sound. W is a consonant.
a unit, not an unit
Unit starts with a Y sound. Y is a consonant.
an empty bucket
a red apple
an open door
"I saw a dog. The dog was black."
"We watched a great movie last night." "Oh, really? What was the movie about?"
"Tom is a teacher. He's the newest teacher at his school."