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English grammar

CEFR B2

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Cleft sentences in English: it was X who, what I need is, and how to move the emphasis

English cannot move words around freely. The word order page explains why: with almost no endings left, order is the only thing telling you who did what, so the subject stays in front of the verb and the object stays behind it. That solves one problem and creates another. If you cannot move a word, how do you show which word you mean?

Speech has an answer: say it louder. John broke the window. Writing does not, and nor does a language learner who has not yet grown a native speaker's instinct for stress. So English built a structure that does the job with words instead of volume. You split the sentence in two and put the important part in its own clause, where it cannot be missed.

It was John who broke the window.

That is a cleft sentence. Cleft means split. There is no new information in it, no extra fact, no change of tense. It is pure emphasis, made out of grammar. And unlike the fronted inversions on the word-order page, this one is not literary at all: clefts are what people reach for in an argument, at work and on the phone, every day.

What the split buys you

Compare the flat version with the two main clefts.

SentenceWhat it emphasises
John broke the window.nothing in particular
It was John who broke the window.John, and not anyone else
What John broke was the window.the window, and not the door
What John did was break the window.the action itself

Same event, four framings. Notice that the emphasised part always lands in the same place: right after it was or right after is. English builds a slot and drops the important word into it. Once you can see the slot, the rest of the topic is mechanical.

It-clefts: it was X who...

The shape is fixed:

it + be + the highlighted part + who / that + the rest

It was my sister who called.It was the noise that woke me.It was in the summer that we moved house.It is the cost that worries me.

Three things to get right.

The linking word. People take who (or that); things take that; times and places take that in this pattern. The rules are the ones on the relative clauses page, with one extra warning: never use what here. It was the noise what woke me is a real thing people say in some dialects, and it will be marked wrong in every exam.

The tense of be. It follows the event, not the moment of speaking. Past event, past be: it was my sister who called. Present situation, present be: it is the cost that worries me.

Agreement. It is the grammatical subject, so be stays singular even when the highlighted part is plural: it was my parents who paid, not it were my parents. The verb inside the second clause, though, agrees with the highlighted part: it is you who are wrong.

The it-cleft is also how English says "and nobody else". Put the negative in the highlighted slot and you get a correction:

It was not the money that mattered.It wasn't me who told her.

That is the natural home of this structure: denying one part of a claim while accepting the rest.

Wh-clefts: what I need is...

The other main type flips the order. The background comes first, in a clause starting with what, and the important part arrives at the end.

what + clause + be + the highlighted part

What I need is a holiday.What worries me is the cost.What she said was completely true.

This is a different tool, not a synonym. An it-cleft points at something; a wh-cleft builds up to something. It buys a beat of delay, which is why it is so common in speech and in argument. What I want is an apology makes the listener wait for the last three words.

To highlight an action rather than a thing, use what + subject + do and finish with a bare infinitive:

What he did was tell everyone.What you should do is call her.What they did was wait.

Not what he did was told everyone. The do carries the tense; the second verb stays plain.

Reverse wh-clefts and the thing that...

The wh-clause can also go at the end, which is the most conversational version of the lot:

A holiday is what I need.That is what I meant.This is what worries me.

And when what feels too abstract, English swaps in a noun: the thing, the reason, the place, the person, the problem.

The thing that worries me is the cost.The reason why I called was to say thank you.The person who helped me was a stranger.All I did was ask a question.

That last pattern, all I did was, is worth learning on its own. It is a cleft with a built-in argument: it says "this and nothing more", which is why it appears in every defensive sentence in the language. All I said was hello.All she wants is an answer. Same bare-infinitive rule as above: all I did was ask, not all I did was asked.

Which one to reach for

A short decision list, in the order you will actually need it.

  • Correcting someone about who or what did something: it-cleft. It was the wind, not me.
  • Delivering a demand or a conclusion, with a pause before it: wh-cleft. What I need is more time.
  • Emphasising an action: what he did was...
  • Minimising: all I did was...
  • Pointing back at something already said: that is what I meant.

If you want the same emphasis in formal written English without a cleft, the fronting and inversion patterns on the word order page do a similar job in a much higher register. Clefts are the everyday version. That is their whole advantage.

Common mistakes

Ranked by how often learners actually make them.

  1. what instead of that in an it-cleft. It was the noise what woke me should be that woke me. What belongs at the front of a wh-cleft, never after the highlighted item.
  2. Making be plural in an it-cleft. It were my parents who paid should be it was my parents who paid. The subject is it, and it is always singular.
  3. A full verb after what he did was. What he did was told everyone should be was tell everyone. Same for all I did was ask.
  4. Repeating the subject. It was my sister who she called has one subject too many. Who is already doing the work: it was my sister who called. This is the same slip as the double subject in relative clauses.
  5. Clefting everything. A cleft emphasises by contrast with plain sentences. Three in a row and the effect dies, and the writing starts to sound like it is arguing with someone who is not there.
  6. Wrong tense in the background clause. What I needed is a holiday mixes times. Keep the two halves consistent: what I need is a holiday or what I needed was a holiday.

Practice

Rewrite each sentence to emphasise the part in brackets. Answers are below.

  1. My brother paid for dinner. (my brother)
  2. I want an answer. (an answer)
  3. The rain stopped the game. (the rain)
  4. He told everyone. (the action)
  5. I only asked a question. (only)

Answers: 1. It was my brother who paid for dinner. 2. What I want is an answer. 3. It was the rain that stopped the game. 4. What he did was tell everyone. 5. All I did was ask a question.

Practise: test yourself

Pick the right one

0/8

Choose the correct word to complete each cleft sentence.

  1. It was my sister took the key.

  2. It was the wind opened the door.

  3. I want is a quiet evening.

  4. he did was tell everyone.

  5. It was in the summer we moved house.

  6. The thing worries me is the cost.

  7. needs to change is the plan.

  8. It was you said it first.

Fill in the blank

0/8

Write the missing word in each cleft sentence.

  1. It my father who taught me to drive.

  2. What I need a long sleep.

  3. All I did ask a question.

  4. It was the dog ate the bread.

  5. is what I meant.

  6. The reason I called was to say thank you.

  7. What she wants more time.

  8. It was not the money mattered.

Matching

0/6

Match each plain sentence to its cleft version.

Frequently asked questions

What is a cleft sentence?
A cleft sentence is one idea split into two clauses so that one part gets all the attention. John broke the window is a single flat statement. It was John who broke the window splits it, puts John in a spotlight and pushes the rest into the background. Cleft means split. Nothing new is being said; the same facts are simply arranged so the listener cannot miss which part matters.
What is the difference between an it-cleft and a what-cleft?
An it-cleft highlights one item, usually a person, a thing or a time: it was my sister who called, it was on Monday that we met. A what-cleft, also called a wh-cleft, highlights an action or a whole idea and builds up to it: what I need is a holiday, what he did was tell everyone. Rough guide: use it was X who for pointing at one thing, and what I ... is for delivering a point at the end of the sentence.
Should I use who or that in it was X who called?
For people, both work. It was my sister who called and it was my sister that called are equally correct, with who slightly more common in careful writing. For things, use that: it was the noise that woke me. For times and places, that is the safe choice in the cleft pattern: it was in the summer that we moved, it was at the station that we said goodbye. Never use what in an it-cleft; it was the noise what woke me is a well-known non-standard form.
Are cleft sentences formal?
No, and this is the useful part. Unlike fronted inversion, clefts are completely ordinary spoken English. It was you who said it first, what I want is an apology, all I did was ask - people say these constantly, often in an argument, because the whole point of a cleft is to insist on one part of the sentence. Learn them and your spoken English immediately sounds less flat.