Appositive clauses look a great deal like relative clauses. Analyze the following examples: what kind of word is the clause attached to? what is the original sentence that the clause was created from?
#1: appositive clause: I like the idea that students can become independent learners.
1. The clause is attached to a noun--the idea.
2. The underlying sentence is: Students can become independent learners.
#2: relative clause: Students who become independent learners can continue to learn after they leave our classes.
1. The clause is attached to a noun--students
2. The underlying sentence is: Students become independent learners.
Based on that analysis, how are these two subordinate clause types different?
A relative clause
includes in its internal structure the same noun that it attaches to. The relative pronoun means the same thing as the noun that the clause is attached to; the relative pronoun has a grammatical role that combines being a connector with a role in the syntax of its clause.
An appositive clause
does not include the noun that it attaches to; the appositive clause is like a linking verb--or an equal sign: the idea = students can become independent learners. The connector that just connects the clause to the noun without playing any internal role in the clause.
can be related to particulate verbs and their noun clause direct objects:
I believe that students can become independent learners.
The belief that students can become independent learners is common among teachers.
I know that students can become independent learners.
Our knowledge that students can become independent learners drives our work.
I feel that students can become independent learners.
My feeling that students can become independent learners is shared by many other teachers.
Grammarians and linguists refer to this process of changing a verb to a noun as nominalization. Notice how the nominalized version has the same grammatical feature as the verb version--the noun clause of the verb version becomes the appositive clause of the noun version.
When analyzing authentic samples, just be careful not to jump to the conclusion that every noun + that combination is a relative clause. Nouns like idea, belief, thought, knowledge, and a few others are often followed by appositive clauses.
Test your knowledge by deciding which of these sentences has an appositive clause and which has a relative clause.
The idea that I shared with my students comes from many years of teaching experience.
The idea that we must work together as a team guides our department's work.
Source Relative Clauses