Therefore, this appositive is restrictive and has no commas. If an appositive is unnecessary to understand the identity of the noun or noun phrase it is identifying, it is nonrestrictive. Nonrestrictive appositives are set off with commas.
restrictive modifier adds information that is not essential to our understanding of the sentence; if we remove it from the sentence, the basic meaning of the sentence does not change. A restrictive modifier identifies, or limits the reference of, the noun it modifies.
Types of Clauses Main Clause or Independent Clause – A main clause is a group of words with a subject and a verb. Subordinate Clause or Dependent Clause – A subordinate clause is a group of words that consists of a subject, a verb and a subordinating conjunction or a relative pronoun.
Restrictive clauses are usually introduced by the relative pronouns that, who, whom, or whose. A restrictive clause can have an identifying function. The astronaut who first stepped on the moon was Neil Armstrong. The restrictive clause in this sentence is who first stepped on the moon.
restrictive modifier adds information that is not essential to our understanding of the sentence; if we remove it from the sentence, the basic meaning of the sentence does not change. A restrictive modifier identifies, or limits the reference of, the noun it modifies.
A restrictive clause introduces information that is necessary to the meaning of the sentence. A nonrestrictive clause can be removed without changing the meaning. Restrictive clauses require no punctuation; nonrestrictive clauses are usually separated from the independent clause with commas.
In a restrictive adjective clause, the information is necessary to the sentence and no commas are necessary. In a nonrestrictive clause, the information is provided to enhance our understanding and must be set off by commas.
restrictive modifier adds information that is not essential to our understanding of the sentence; if we remove it from the sentence, the basic meaning of the sentence does not change. A restrictive modifier identifies, or limits the reference of, the noun it modifies.