Cleft sentences sound really horrible and complicated and scare the crap out of some students but it is really not so complicated.
Cleft sentences are used to emphasise a noun(thing)
Base sentence - Andrzej went to Amsterdam last weekend
1st version - It was Andrzej who went to Amsterdam last weekend - focus on who
2nd version - It was Amsterdam that Andrzej went to last weekend - focus on where
3rd version - It was last weekend that Andrzej went to Amsterdam - focus on when
The base structure is
It + 'BE' + focus(noun) + relative clause
This is often used to correct people in spoken English
Q. Did Kamil go to Amsterdam last weekend?
A. No, it was Andrzej who went to Amsterdam last weekend. Kamil went to Berlin.
NB 'It' can be replaced by a noun phrase in certain circumstances
The reason Kamil went to Berlin was to play chess
Psuedo cleft sentences sound even worse but are just as easy. They emphasise an action.
Base sentence - Norbert washed his socks last weekend.
1st version - What Norbert did was wash his socks last weekend. - focus on action and time
2nd version - What Norbert did last weekend was (to) wash his socks - focus on action
The base structure is
What + noun + 'BE' + focus (action)
This structure is often used to clarify things
Three cubed is equal to twenty-seven. What I mean is three times three times three is twenty-seven
Or your likes and dislikes
What I really like is eating chocolate in front of the TV :)
Or to correct people
Did you say you would give me your car?
No, what I said was that I will lend you my car for the week!
