Articles the vs. a/an Practice 1

identity not yet establishedidentity already established by context/modifier
He wants to buy a blue car.He wants to buy the blue car he saw last week.
I met a nice girl yesterday.The girl next door is really nice.
cannot be used before pluralscan be used before plurals
I met a nice person yesterday.The people I met were nice.

Decide whether to use a, an, or the for each of the following sentences.