Relative clauses

RELATIVE PRONOUNS.
that 
el que, la que, los que, las que, lo que
who 
quien, quienes
which 
el cual, la cual, los cuales, las cuales, lo cual
whom 
a quien, a quienes
whose
de quien, de quienes, cuyo, cuya, cuyos, cuyas
what
lo que, lo cual 

OMISION DEL RELATIVO

Se omite el pronombre relativo:
1.Cuando el relativo hace de complemento:
the book (that) I bought, el libro que compré.
2.Si está regido por preposición, ésta puede colocarse al final y omitirse o no el relativo: 
the place (that) we went to, el lugar al que fuimos.
3.Con that, la preposición se ubica siempre al final: 
I bought the book that you told me about, compré el libro del cual me hablaste.

 
EJEMPLOS CON PRONOMBRES RELATIVOS

I don’t know who was here.

I personally know that author whose books give so much pleasure.

The lessons which she liked better were those which she learned from others.

That was the subject which I was talking about.

I could not understand what they wanted to know.

This is exactly what I wanted to find out.

My brother was the man that (who) was here a moment ago.

The independence that Argentina obtained in 1810 was not recognized until 1816.

Defining Relative Clauses

Defining relative clauses (also called identifying relative clauses or restrictive relative clauses) give detailed information defining a general term or expression. Defining relative clauses are not put in commas.

Imagine, Tom is in a room with five girls. One girl is talking to Tom and you ask somebody whether he knows this girl. Here the relative clause defines which of the five girls you mean.

Do you know the girl who is talking to Tom?

Defining relative clauses are often used in definitions.

A seaman is someone who works on a ship.

Object pronouns in defining relative clauses can be dropped. (Sentences with a relative clause without the relative pronoun are called Contact Clauses.)

The boy (who/whom) we met yesterday is very nice.

Non-Defining Relative Clauses

Non-defining relative clauses (also called non-identifying relative clauses or non-restrictive relative clauses) give additional information on something, but do not define it. Non-defining relative clauses are put in commas.

Imagine, Tom is in a room with only one girl. The two are talking to each other and you ask somebody whether he knows this girl. Here the relative clause is non-defining because in this situation it is obvious which girl you mean.

Do you know the girl, who is talking to Tom?

Note: In non-defining relative clauses, who/which may not be replaced with that.

Object pronouns in non-defining relative clauses must be used.

Jim, who/whom we met yesterday, is very nice.

EXERCISES
http://www.ego4u.com/en/cram-up/grammar/relative-clauses/exercises?02
http://www.ego4u.com/en/cram-up/grammar/relative-clauses/exercises?05
http://www.ego4u.com/en/read-on/countries/uk/tour/stonehenge#exercises
http://www.ego4u.com/en/cram-up/grammar/relative-clauses/exercises
http://www.ego4u.com/en/cram-up/grammar/relative-clauses/exercises?04
http://www.ego4u.com/en/cram-up/tests/relative-clauses-2