GRAMMAR

The Relative Clauses have two clauses:

DEFINING RELATIVE CLAUSES

They are an essential part of the meaning of a sentence, therefore they cannot be left out. They basically define who or what we are talking about.

	Person	Thing
Subject	who (that)	that (which)
Object	- (that)	- (that)

The relative pronouns can be dropped when it defines the object of the clause.

Example

The paramedic who helped the boy was Frank. (subject)
The paramedic I found more helpful was Frank. (object)
The treatment that helped him most was resting on one side. (subject)
The treatment he liked best was resting on one side. (object)

that is a subject after the following: superlatives, all, every (thing), some (thing) no (thing), and only

He cooked some of the best food that's ever been made.
All that's needed is a little patience.
Don't break anything that's expensive.
The only thing that matters

"That" is omitted when it is the object.

prepositions

This is the man I was talking to you about.
The people I live with are just fun.

The prepositions can come either before the relative pronouns or at the end of the relative clause.

Second relative clause

Someone that I greatly admire, but who I've never met, is Mr. Brown.

A second relative, introduced by and or but, usually takes a wh- pronoun, not that