USE OF It-CLEFTS in Writing
Prince (1978) distinguishes two type of it-cleft sentences in English---stressed focus (SF) and informative-presupposition (IP). The former contains known information in its presupposed part (i.e., the relative clause) and is used for emphasis, while the latter contains new information in its presupposed part and introduces this new information at the end of the sentence for rhetorical effect: