relative clauses are participle clauses which follow a noun. They are like relative clauses, but with the relative pronoun and auxiliary verb (if there is one) left out.
Because they modify nouns, (reduced) relative clauses are occasionally referred to as adjective clauses. Reduced relative clauses are used most often instead of defining relative clauses, which are what we'll be mainly looking at.
Reduced Relative Clauses
You may remove the relative pronoun and reduce your sentence in certain conditions
The boy who wants to talk to you is waiting for you.
The boy wanting to talk to you is waiting for you.
Relative Clause Reduction Rules
1. In defining clauses, we can omit the relative pronoun in the position of object.
The boy who / whom / that you don’t like much wants to talk to you.
The boy you don’t like much wants to talk to you.
that when the relative pronoun is the object of a defining relative clause, we can omit (leave out) who, which or that.
The children (who) I taught all became geniuses. - direct object •
This is the hotel (which) I was telling you about. - object of the preposition about
They're going to have to sell the house (that) they bought only a year ago. - direct object
Note: In non-defining sentences you neither omit the relative pronoun nor use "that".
My mother, who / whom that you met yesterday, wants to talk to you.
My mother you met yesterday...
2. We can use participles when reducing the sentence.
a) Present Participle Ving (simultaneous)
We stood on the bridge which connects the two halves of the city.
We stood on the bridge connecting the two halves of the city.
b) Past Participle V3 or being V3 (passive simultaneous)
Two boy who was attacked by a dog was taken to hospital.
Two boy attacked by a dog was taken to hospital. (Past Participle)
Omitting the -ing form when it is followed by a prepositional phrase
can omit the