Cleft sentences are grammatical structures that divide (or "cleave") a simple sentence into two clauses to emphasize a particular piece of information. They're called "cleft" from the Old English word meaning "split." According to Biber et al. (1999), cleft sentences are particularly common in academic and formal writing where precision and emphasis are important. They allow speakers to highlight specific information and control the flow of information in discourse.

It-Cleft Sentences

It-clefts begin with It + be + emphasized element + that/who clause. This structure puts emphasis on the element immediately after "be."

Basic sentence: Sarah broke the window yesterday.
It-cleft (emphasize Sarah): It was Sarah who broke the window yesterday.
It-cleft (emphasize window): It was the window that Sarah broke yesterday.
It-cleft (emphasize time): It was yesterday that Sarah broke the window.

• It was John who called you last night. (emphasizes who called)
• It was her dedication that made the difference. (emphasizes what made the difference)
• It was in Paris that we first met. (emphasizes where)
• It is because of you that I'm here. (emphasizes reason)

Wh-Cleft Sentences (Pseudo-Clefts)

Wh-clefts start with a wh- clause (what, where, when, why, how) followed by be and the emphasized information. These are also called pseudo-clefts.

Basic sentence: I need a vacation.
Wh-cleft: What I need is a vacation.

Basic sentence: She resigned because of the stress.
Wh-cleft: Why she resigned was because of the stress.

• What I want is to be left alone.
• What surprised me was his reaction.
• Where we went was to the mountains.
• How he succeeded was through hard work.
• What bothers me most is the noise.

Reverse Wh-Clefts

Reverse wh-clefts place the emphasized element before the wh-clause.

• A vacation is what I need right now.
• Through hard work is how he succeeded.
• Your support is what matters most.
• The truth is what we're looking for.

All-Clefts

All-clefts use All (that) to emphasize exhaustiveness or exclusivity.

• All I want is some peace and quiet.
• All she did was apologize.
• All we need is more time.
• All that matters is your safety.

When to Use Cleft Sentences

• To correct misinformation: It wasn't John who called; it was Sarah.
• To introduce new information dramatically: What shocked everyone was his confession.
• To emphasize contrast: It's quality that matters, not quantity.
• In answers to questions: "Who ate the cake?" → It was Tom who ate it.