CLEFT SENTENCE is a construction that makes possible to put special emphasis on a particular sentence function. This special structure is called CLEFT SENTENCE because to form such a sentence we cleave the sentence into two parts in a way that emphasized part takes place in the first section. Consequently, structural pattern of a cleft sentence remains as:
It + be + emphasized sentence function FIRST PART + (who / that )………… SECOND PART
Consider the following sentence: Peter wrote Mary a love letter in Paris Subj V Oi Od A 1 last week. A 2
Emphasizing the Subject Function : Sentence: Peter wrote Mary a love letter in Paris last week. Pattern: It + be + emphasized sentence function + (who / that )…………
Cleft Sentence: (considering the tense ) It was Peter who wrote a love letter to Mary in Paris last week. (It was Peter who wrote Mary a love letter in Paris last week - also acceptable)
Emphasizing the Direct Object Function : It was a love letter that Peter wrote (to) Mary in Paris last week
Emphasizing the Indirect Object Function : It was Mary Peter wrote a love letter to in Paris last week.
Emphasizing the Adverbial (1) Function : It was in Paris that Peter wrote Mary a love letter last week.
Emphasizing the Adverbial (2) Function : It was last week that Peter wrote Mary a love letter in Paris.