We use adjective clauses to identify or give more information about a person, place or thing (noun). Unlike an adjective word, which comes before the noun it modifies, the adjective clause comes after the noun. We usually use relative pronouns to introduce the adjective clause.
Relative pronouns are listed below.
who, that modifies person / people
Students who arrive early will be able to review for the test.
Jane Case, who arrived earlier today, will be our next speaker.
whose modifies possession
The man whosewife is from Jordan is coming tomorrow.
which, that modifies thing
The pencils which are on the table belong to the teacher.
Her eyes, which sparkled with joy, told the story of what had happened.
The young man took the money which his father gave him and left for a far city.
where modifies place
The students had a picnic in the park where the lake is.
when modifies time
They knew they had to leave the day when the storm struck.
Identifying and non identifying adjective clauses
It is important to understand identifying and non-identifying adjective clauses because it helps us know when to use commas. We say an adjective clause is identifying when the information is necessary for the meaning of the sentence. In this case, we do not use commas to set it apart. However, if the information is not necessary for the meaning of the sentence, we say the adjective clause is non-identifying. Therefore, we use commas to set it apart.