What Are Restrictive and Non-restrictive Structures?
When we use the term 'restrictive' for the elements in a group, we mean that the part is essential for the sentence (whether to complete its meaning semantically or to complete it grammatically).
Non-restrictive parts of a sentence are the ones that can be omitted from the sentence without causing any harm to the formation or meaning of it.
Restrictive and Non-restrictive Clauses and Phrases: Types
There are two types of restrictive and non-restrictive structures:
Relative clauses and appositives are nominal and adjectival structures that are used to give further information about a noun.
Relative Clauses as Restrictive Clauses
Sometimes using a relative clause is needed to have an exact description about something and using them makes a difference in the meaning of the sentence. Here are the examples:
Relative Clauses as Non-restrictive Clauses
Sometimes using the relative clause provides unnecessary information about a noun, so they are set off by commas, and omitting them from the sentence would not cause any harm. Here are a few examples that might help learn them better:
These nice people are all friends of mine,
American English or British English?
Remember restrictive relative clauses are not set off by commas, this means that they do not have any commas on both sides, but non-restrictive relative clauses are used between commas when they are used in the middle of the sentence. They are preceded by a comma when they are used at the end of the sentence. Here are a few examples:
I called John,
Appositives as Restrictive Phrases
Appositives do not usually give important information; however, when we are referring to one particular member of a group, we use a proper noun as a restrictive noun. Here are the examples:
Here, the person has more than one friend.
In this example, the person has more than one brother.
Appositives as Non-restrictive Phrases
Non-restrictive appositive nouns or noun phrases are used to give more information; but omitting them from the sentence would not make any harm or difficulty in understanding the meaning of the sentence. Check out the examples:
The best chef ever in this area,
When non-restrictive appositive nouns or noun phrases are used at the beginning of a sentence, they are followed by a comma, at the middle position they are set off by commas and at the end of a sentence, they are preceded by a comma. Check out the examples:
The tall man standing over there,
The last station,
I bought the chocolate you like,