Cleft sentence
A cleft sentence is a complex sentence (one having a main clause and a dependent clause) that has a meaning that could be expressed by a simple sentence. Clefts typically put a particular constituent into focus. This focusing is often accompanied by a special intonation.
In English, a cleft sentence can be constructed as follows:
where it is a cleft pronoun and X is usually a noun phrase (although it can also be a prepositional phrase, and in some cases an adjectival or adverbial phrase). The focus is on X, or else on the subordinate clause or some element of it. For example:
It's Joey (whom) we're looking for.
It's money that I love.
It was from John that she heard the news.
It was meeting Jim that really started me off on this new line of work.
Types
English is very rich in cleft constructions. Below are examples of other types of clefts found in English, though the list is not exhaustive (see Lambrecht 2001 for a comprehensive survey, Collins 1991 for an in-depth analysis of it-clefts and wh-clefts in English, and Calude 2009 for an investigation of clefts in spoken English).