“The” is a definite article because it is used when the noun is specific or particular (not “any lake,” but “the lake”), while “a/an” are the indefinite articles (“a lake,” meaning “any lake” not a specific lake).
When to use "the" is often the most difficult to figure out because it depends on the structure of the rest of the sentence.
For example, both of the following sentences are correct:
1. Three houses on my block have fenced-in yards.
2. The three houses on my block with fenced-in yards are blue.
What about going to Spain in
January?
He has never been to Alps
before.
Listen! Adam is playing
piano.
Alex goes to work by car.
We often see our cousins over
Christmas.
Don't be late for school.
I always listen to radio in
the evening.
My mother likes flowers very
much.
See you on Friday.
I like flowers in our
garden.
Our children go to school on
foot.
My friends Williams moved to
New York last June.
My sister often stays at
home.
Summer of 2021 was hot and
dry.
The Hotel is on corner of
26th Street and 7th Avenue.
Our children like sweets.
Largest lake on German
territory is Lake Constance.
Last year we visited Tower.
Mount Everest is the highest
mountain on earth.
Our mother lives in
Philippines.
Guadalcanal belongs to
Solomon Islands.
What about going to Spain in
January?
He has never been to the Alps
before.
Listen! Adam is playing
the piano.
Alex goes to work by car.
We often see our cousins over
Christmas.
Don't be late for school.
I always listen to the radio in
the evening.
My mother likes flowers very
much.
See you on Friday.
I like the flowers in our
garden.
Our children go to school on
foot.
My friends the Williams moved to
New York last June.
My sister often stays at
home.
The summer of 2021 was hot and
dry.
The Hotel is on the corner of
26th Street and 7th Avenue.
Our children like sweets.
The largest lake on German
territory is Lake Constance.
Last year we visited the Tower.
Mount Everest is the highest
mountain on earth.
Our mother lives in
the Philippines.
Guadalcanal belongs to
the Solomon Islands.
