If you don’t know what a cleft sentence is, you’re not alone. But you’ve certainly used this type of sentence. Perhaps you wanted to emphasize a particular piece of information: It was the cat that frightened me. Perhaps your intention was to correct a false assumption: It was not the cat that frightened me. Or perhaps you wanted to add a tinge of drama to your declaration: There are no words that could describe how frightened I was by the cat. These are all examples of cleft sentences.
But what is a cleft sentence, really? A cleft sentence is a special type of grammatical construction that emphasizes a particular element of a sentence by placing that element in a separate clause. The clause that introduces a cleft sentence may begin with it or there, as in the examples above, or with another word, such as what (What frightened me was the cat) or that (That is the cat that frightened me). For instance, the sentence It was the cat that frightened me places emphasis on the cat, the implication being that the cat, not something else, was the source of fright. Forgoing the it-clause and jumping straight to the cat (The cat frightened me) or reconfiguring the sentence so that it begins with I (I was frightened by the cat) doesn’t convey the same emphasis. You might protest: Wouldn’t another solution be to simply change the intonation of one’s voice, in this instance by stressing the word cat? While that might work in spoken utterances, writing may require a cleft sentence in order to communicate a point.
A cleft sentence can be a statement of fact (It was the cat that frightened me). It can function as a negation of something previously said (It was not the cat that frightened me). It can also take the form of a question (Was it the cat that frightened you?). Writers may also use a cleft sentence for dramatic effect (It was at midnight that I was awakened by the startling sound of a cat screeching outside my window). But like other types of rhetorical devices, cleft sentences can quickly become stale with overuse. Consider whether the cleft sentences you use in your writing serve a purpose or whether the point would be just as clear (and more concisely articulated) without them.