Relative Clauses

We use relative clauses to give additional information about something without starting another sentence. By combining sentences with a relative clause, your text becomes more fluent and you canavoid repeating certain words.
How to Form Relative Clauses 
Imagine, a girl is talking to Tom. You want to know who she is and ask a friend whether he knows her. You could say:
A girl is talking toTom. Do you know the girl?
That sounds rather complicated, doesn't it? It would be easier with a relative clause: you put both pieces of information into one sentence. Start with the most importantthing  – you want to know who the girl is.
Do you know the girl …
As your friend cannot know which girl you are talking about, you need to put in the additional information  – the girl is talking toTom. Use „the girl“ only in the first part of the sentence, in the second part replace it with the relative pronoun (for people, use the relative pronoun „who“). So the final sentence is:
Do you knowthe girl who is talking to Tom?
Relative Pronouns 
relative pronoun | use | example |
who | subject or object pronoun for people | I told you about the woman who lives next door. |
which |subject or object pronoun for animals and things | Do you see the cat which is lying on the roof? |
which | referring to a whole sentence | He couldn’t read which surprised me. |
whose | possession forpeople animals and things | Do you know the boy whose mother is a nurse? |
whom | object pronoun for people, especially in non-defining relative clauses (in defining relative clauses wecolloquially prefer who) | I was invited by the professor whom I met at the conference. |
that | subject or object pronoun for people, animals and things in defining relative clauses (who or which are alsopossible) | I don’t like the table that stands in the kitchen. |
Subject Pronoun or Object Pronoun? 
Subject and object pronouns cannot be distinguished by their forms - who, which, that are used for...