DEFINING RELATIVE CLAUSES (They are Essential clauses and do not require commas. A relative clause is essential when you need the information it provides.)
a) relative pronoun=subject
The man is a scientist. The man lives here. (HUMAN)
>>> The man who/that lives here is a scientist.
(it might be reduced: The man living here is a scientist)
The car is new. The car is parked outside. (NONHUMAN)
>>> The car which/that is parked outside is new.
(it might be reduced: The car parked outside is new)
b) relative pronoun=object
The man is a scientist. I mentioned the man. (HUMAN)
>>> The man who/whom/that/Ø I mentioned is a scientist.
The car is outside. John owns the car. (NONHUMAN)
>>> The car which/that/Ø John owns is outside.
WHOM: The woman to whom you were speaking is a doctor.
The woman who you were speaking to is a doctor.
WHOSE (possessive): He's the man whose car was stolen last week.
2. NONDEFINING RELATIVE CLAUSES (They are nonessential and do
require commas, they only give additional information)
My mother is thinking of opening a restaurant. My mother is an excellent cook.
>>> My mother, who is an excellent cook, is thinking of opening a restaurant.
I’m planning to grow roses. I find roses quite beautiful.
>>> I’m planning to grow roses, which I find quite beautiful.
Notes
In non-defining clauses, you cannot use 'that' instead of who, whom or which.
You cannot leave out (omit)the relative pronoun, even when it is the object of the verb in the relative clause:
He gave me the letter, which I read immediately
The preposition in these clauses can go at the end of the clause, e.g.
This is Stratford-on-Avon, which you have all heard about.
3. Exercises
a) Very easy:
https://www.ego4u.com/en/cram-up/grammar/relative-clauses/exercises?02
https://www.ego4u.com/en/cram-up/grammar/relative-clauses/exercises?09
https://www.ego4u.com/en/read-on/countries/uk/tour/stonehenge#exercises
https://www.ego4u.com/en/read-on/countries/usa/tour/san-francisco#exercises
More Rules and exercises (perfect English grammar)
Rules
http://www.perfect-english-grammar.com/relative-clauses.html
1.WHO or THAT ?
http://www.perfect-english-grammar.com/relative-clauses-exercise-1.html
2. The relative pronoun is the object of the relative clause (this means you can drop 'who', 'which' or 'that' if you want)
http://www.perfect-english-grammar.com/relative-clauses-exercise-2.html
3. In these exercises, sometimes the relative pronoun is the object of the relative clause (this means you can drop 'who', 'which' or 'that' if you want) and sometimes it's the subject (you can't drop 'who', 'which' or 'that')
http://www.perfect-english-grammar.com/relative-clauses-exercise-3.html
http://www.perfect-english-grammar.com/relative-clauses-exercise-4.html
b) Quite easy:
Subject Pronouns or Object Pronouns?
https://www.ego4u.com/en/cram-up/grammar/relative-clauses/exercises?05
Relative Pronouns - necessary or not?
https://www.ego4u.com/en/cram-up/grammar/relative-clauses/exercises?10
https://www.ego4u.com/en/cram-up/grammar/relative-clauses/exercises
c) Not so easy:
https://www.ego4u.com/en/cram-up/grammar/relative-clauses/exercises?11
Relative pronouns – necessary or not?
https://www.ego4u.com/en/cram-up/grammar/relative-clauses/exercises?06
Relative clauses - defining or non-defining?
https://www.ego4u.com/en/cram-up/grammar/relative-clauses/exercises?04
Non-Defining Relative Clauses
https://www.ego4u.com/en/cram-up/grammar/relative-clauses/exercises?12
Forming relative clauses
https://www.ego4u.com/en/cram-up/grammar/relative-clauses/exercises?07