The intuition: established information first, new information last
A wh-cleft, or pseudo-cleft, divides a simple message into two parts. The first, the what-clause, names a topic the listener already has in mind. The second, after is or was, supplies the point you want to make. A brief pause before the focus can create anticipation: what exactly will be identified?
The focus often supplies new information or corrects an expectation, but it can also recall or deliberately emphasize something already known. Novelty is not the only issue: consider whether this distribution of attention helps the particular utterance.
What + subject + verb + is/was + focus → topic, often established → focus, often new
- subject / S —
- The grammatical subject: who or what the clause is about; the verb agrees with it. In The book was written, the book is the subject, although someone else does the action.
- verb / V —
- A word for an action or state, such as work or be. The pattern determines its form.
What the museum lacks is a proper archive of its early donations.
What the museum lacks is a proper archive of its early donations.
The topic is what the museum lacks; the new, important information is the archive. That is the identification the listener is waiting for.
What impressed the jury was the restraint of the design.
What impressed the jury was the restraint of the design.
The wh-clause introduces the topic of the jury’s reaction, and the focus identifies what caused it.
What I'd like to hear is how the figures were verified.
What I'd like to hear is how the figures were verified.
An embedded question can also be the focus: the speaker identifies exactly what they want to hear about.
The form: what-clause, be, focus
The what-clause functions as the subject, followed by a form of be and then the focus. It uses statement word order, without question inversion: What the staff wanted …, not What did the staff want …. When what itself is the subject, auxiliary do is unnecessary: What annoyed the staff …. A stressed What did annoy the staff … is possible specifically as emphatic contrast.
A preposition belonging to the verb stays inside the clause: What the panel disagreed with was …. Do not add an extra pronoun before or after be. The what-clause is followed directly by is or was.
What + (subject) + verb (+ preposition) + is/was + focus
- subject / S —
- The grammatical subject: who or what the clause is about; the verb agrees with it. In The book was written, the book is the subject, although someone else does the action.
- verb / V —
- A word for an action or state, such as work or be. The pattern determines its form.
- preposition —
- A word showing a relationship, such as in, on or from: from Ukraine.
What bothers the inspectors is the state of the stairwells.
What bothers the inspectors is the state of the stairwells.
What is the subject of the clause, so no auxiliary is needed.
What the editors relied on was a single, outdated survey.
What the editors relied on was a single, outdated survey.
The preposition on remains with relied inside the clause.
What caught my eye was a footnote on page ninety.
What caught my eye was a footnote on page ninety.
The clause uses ordinary past tense, followed by was before the focus.
What can occupy the focus
The focus is most often a noun phrase. Other structures can follow is or was too: a gerund or infinitive, a that-clause, an embedded question introduced by why, how, who or whether, or a contrast of not X but Y.
Choose the focus structure according to what you want to highlight: a thing, an action, a conclusion or an open question. This is connected to your choice of starting point, such as what is missing versus what has become clear.
What the neighbours want is a pedestrian crossing.
What the neighbours want is a pedestrian crossing.
The focus is a noun phrase.
What he hates is waiting in queues.
What he hates is waiting in queues.
A gerund occupies the focus. The what-clause contains a verb expressing an attitude, rather than do.
What the evidence suggests is that the effect is real but small.
What the evidence suggests is that the effect is real but small.
A that-clause is the focus: the conclusion the speaker wants to emphasize.
What nobody has explained is why the figures were revised.
What nobody has explained is why the figures were revised.
An embedded question is the focus: an issue that remains unanswered.
What remains to be settled is whether the fee applies retroactively.
What remains to be settled is whether the fee applies retroactively.
The whether-clause presents the focus as a choice between two possibilities.
Do-clefts: highlighting an action
To highlight an action, use do in the what-clause and an infinitive after be: What I do is write; What she did was compare. The tenses often refer to the same time frame, but they do not have to match mechanically: What I learned then is that careful checking matters.
In the basic action pattern after do, did or done, the infinitive can appear with or without to: What I do is (to) check the figures. In the examples with did, was is followed by compare, not compared. If progressive aspect matters, a corresponding -ing form is possible: What she is doing is checking the figures.
What + subject + do, in the required tense + is/was + (to) + verb
- subject / S —
- The grammatical subject: who or what the clause is about; the verb agrees with it. In The book was written, the book is the subject, although someone else does the action.
- verb / V —
- A word for an action or state, such as work or be. The pattern determines its form.
What the translator did was compare every line with the original.
What the translator did was compare every line with the original.
The action is highlighted: the base form compare follows was.
What I usually do is write the conclusion first.
What I usually do is write the conclusion first.
A present-tense habit: do — is — base form.
What the council has done is to postpone the decision.
What the council has done is to postpone the decision.
After the present perfect here, to is optional. The sentence is also correct without it.
Be: agreement and tense
A what-clause often takes singular is or was because it presents a unified topic. Choose the tense of be according to the intended meaning: a past episode usually takes was, while a current assessment may take is. Do not mechanically copy the tense of the verb inside the clause.
Before a plural focus, both is and are are possible: What the shelter needs is/are extra beds. Both patterns occur; the singular-focus examples here require is. In What happened was (that)…, that can be omitted.
What worried the engineers then was the cost of the foundations.
What worried the engineers then was the cost of the foundations.
This example describes a past situation, so be is also in the past tense.
What worries the engineers now is the delivery schedule.
What worries the engineers now is the delivery schedule.
This example concerns the present, so it uses is.
What happened next was that the roof gave way.
What happened next was that the roof gave way.
In a narrative, What happened … was is a natural way to introduce an event.
Relative what, rather than interrogative what
In this cleft, what means the thing that, rather than asking What?. A useful check is to replace the what-clause with the thing(s) that … and follow it with be. When what introduces an embedded question, as in She asked what …, that is a different construction without a focus after be.
Other wh-words appear in certain established frames: where for the location of a problem or a point in an argument, and how for a manner. What remains the main and safest pattern to learn. When identifying people, English uses other structures such as The person who …, covered by separate rules.
She asked what the inspectors had found.
She asked what the inspectors had found.
This is an embedded question. There is no be + focus after the what-clause, so it is not a cleft.
What the inspectors found was mould behind every wall.
What the inspectors found was mould behind every wall.
This is a cleft: what means the thing that, and mould is the focus.
Where the argument breaks down is in its second premise.
Where the argument breaks down is in its second premise.
Where replaces what: the focus identifies the location of the weak point.
Why use a cleft? Contrast, attitude and narrative
Clefts work well for correcting expectations—not X but Y—highlighting your attitude, as in What impressed me …, recounting an event, as in What happened was …, and emphasizing an action.
A cleft lets you highlight the focus and prepare the listener for it. A pause is possible but not compulsory: the particular intonation and degree of newness depend on the speech and context.
What the museum needs is not a bigger building but a clearer purpose.
What the museum needs is not a bigger building but a clearer purpose.
A contrast corrects the initial expectation.
What I said was that the deadline might move, not that it had.
What I said was that the deadline might move, not that it had.
A correction of someone’s account of what was said: the focus gives the exact content.
What strikes me about the proposal is how little it says about maintenance.
What strikes me about the proposal is how little it says about maintenance.
An evaluative reaction: the wh-clause introduces the topic of the speaker’s response.
What happened was that the ferry arrived an hour early and left without us.
What happened was that the ferry arrived an hour early and left without us.
A narrative use: a whole clause identifies the event.
Scope and restraint
Not every sentence needs to be a cleft. Several in a row can weigh down a passage, but can also create deliberate parallelism. Choose repetition according to the purpose and rhythm of the text, rather than following a fixed ban.
Related constructions are outside this lesson’s scope: reversed order with the focus first, as in A clearer purpose is what the museum needs; clefts with all or thing, as in All I want is … or The thing that …; and it-clefts. Here, the aim is simply to distinguish them from what-clefts. An ordinary simple sentence often remains the best choice, especially when new information is already in the subject.
The museum needs a clearer purpose.
The museum needs a clearer purpose.
A simple sentence sounds more natural when no special emphasis is needed.
What we measured was latency. What we found was jitter. What we fixed was the router.
What we measured was latency. What we found was jitter. What we fixed was the router.
The three clefts create a parallel summary of stages. If that rhythm is unnecessary, keep one emphasis and simplify the rest. Repetition itself is not an error.
Common mistakes
Incorrect:What troubles the board are the absence of a clear plan.
Correct:What troubles the board is the absence of a clear plan.
Be agrees with the singular what-clause, and the focus is singular too. Are is incorrect in this example.
Incorrect:What the auditor did was ignored the warning signs.
Correct:What the auditor did was ignore the warning signs.
In this do-cleft, was is followed by the base form, optionally with to, rather than a past-tense verb.
Incorrect:What did the residents object to was the new parking charge.
Correct:What the residents objected to was the new parking charge.
The subject inside the clause is the residents, so use statement word order, without question inversion or auxiliary did.
Incorrect:What the panel focused was the cost of delay.
Correct:What the panel focused on was the cost of delay.
The preposition belonging to the verb remains inside the clause: focus on.
Incorrect:Which we lack is a shared vocabulary.
Correct:What we lack is a shared vocabulary.
This cleft begins with what, meaning the thing that. Which or that does not form this construction here.
Incorrect:What I need it is a quiet week.
Correct:What I need is a quiet week.
Be follows the what-clause directly. The pronoun it is unnecessary here.