Why use an it-cleft? Emphasis, contrast and correction
Restructure a sentence to highlight a subject, object or circumstance: It + is/was + focused element + that/who…. The basic event remains, but the construction changes how information is presented and often suggests 'this particular thing, rather than another'. Whether it is appropriate depends on context.
Cleft constructions are common in both speech and writing. They help highlight the intended part of a message, especially when intonational stress alone is insufficient or unavailable in written text.
An it-cleft often corrects an earlier false or incomplete statement. It can express a direct 'not X but Y', rather than emphasis in the abstract.
It was the delayed shipment that triggered the client's complaint.
It was the delayed shipment that triggered the client's complaint.
The focus is the delayed shipment as the cause, rather than the fact of the complaint itself.
It wasn't the intern who missed the deadline — it was the reviewer.
It wasn't the intern who missed the deadline — it was the reviewer.
A typical correction: the first part rejects the assumption, and the second identifies the actual person responsible.
The frame: It + is/was + focus + that/who
In the basic pattern, it is followed by be, then the focused element and the following clause. That suits different kinds of focus; who suits people. Choose is or was according to perspective. It is Anna who won yesterday is possible when identifying the winner now of an earlier event.
A common mistake is to put that immediately after was, leaving the focus on the wrong side of the linker or omitting it altogether. This breaks the construction.
Be agrees with it, not with the focused element. Use third-person singular it is / it was even when the focus is plural.
It + is/was + [focused element] + that/who + [remainder of the original sentence]
It is the youngest researchers who tend to challenge the established models.
It is the youngest researchers who tend to challenge the established models.
The statement is general, so was is unnecessary. The focus is plural, but be remains is.
It was a single missing signature that held up the entire contract.
It was a single missing signature that held up the entire contract.
The focus a single missing signature sits precisely between was and that. Do not move that directly next to was.
What can be focused? Subject, object or circumstance
An it-cleft can foreground the subject performing an action, its object, or a circumstance of time, place or reason. The type of focus does not change the frame; it changes which part of the simple sentence moves immediately after be.
That is a common neutral linker in this cleft pattern. Who is also used for a person. When and where occur with suitable time or place focuses in some constructions, but naturalness depends on the particular pattern. Do not substitute linkers mechanically.
Both who and that are possible for a person. Who explicitly marks a human referent, but that is also natural and does not make the identification less precise.
It was Dr. Alvarez who first questioned the sample's authenticity.
It was Dr. Alvarez who first questioned the sample's authenticity.
The focus is a person functioning as subject, so who is natural. That is also possible.
It was the northern route that the committee ultimately approved.
It was the northern route that the committee ultimately approved.
The object is focused, while the subject the committee remains in the that-clause.
It was in the basement archive that the missing ledger turned up.
It was in the basement archive that the missing ledger turned up.
That connects the remainder of the sentence to the focused place phrase in the basement archive.
Negative time clefts: It wasn't until X that Y
It wasn't/isn't until… that… highlights the earliest point at which something happened or happens: 'only then'. Context may suggest lateness, but lateness is not an obligatory meaning of the construction.
When expressing that an event happened only at that point, the that-clause is affirmative: It wasn't until Friday that the report was finished. Do not mechanically add not to it because the opening is negative.
A negative that-clause is possible when non-occurrence or absence is itself the intended content. Two negatives are therefore not always an error. Check which event and time you intend to describe.
It + wasn't/isn't + until + [time/event] + that + [affirmative event clause]
- clause —
- A construction with a verb, often with its own subject: when I arrived. A non-finite clause may leave the subject unspoken: to get home.
It wasn't until the second audit that the discrepancy came to light.
It wasn't until the second audit that the discrepancy came to light.
The event clause is affirmative, came to light, although the introductory part is negative.
It isn't until the final review that reviewers see the raw data.
It isn't until the final review that reviewers see the raw data.
Isn't describes a general, repeated order within a process rather than a single past event.
Cleft versus pseudo-cleft: two strategies for emphasis
A pseudo-cleft or wh-cleft creates emphasis without initial It: What + [clause] + is/was + [focus]. The focus comes at the END, after was, rather than between be and the linker as in an it-cleft.
Both strategies can present the same fact: It was a faulty valve that caused the pressure drop and What caused the pressure drop was a faulty valve communicate the same event through different syntax. An it-cleft often gives more direct emphasis or correction; a pseudo-cleft can reveal the cause more gradually.
The most common pseudo-cleft starts with what. Other wh-words, such as who, where and why, also occur in related constructions, but this lesson practises only the it-cleft ↔ what-pseudo-cleft pair. Wider pseudo-cleft patterns are outside its scope.
It was the printer's driver update that caused the outage.
It was the printer's driver update that caused the outage.
In the it-cleft, the focus sits directly between was and that.
What caused the outage was the printer's driver update.
What caused the outage was the printer's driver update.
The pseudo-cleft gives the same focus, moved to the end after was.
Register and boundaries: when a cleft is unnecessary
Clefts are natural in spoken and written English. Use one for clear emphasis or contrast. Without that purpose, a simple sentence is usually easier to read.
Do not confuse an it-cleft with neighbouring patterns using it. Anticipatory it with a reporting verb, It is said/believed/reported that X, postpones the entire clause rather than extracting one element. It + adjective + that/to, as in It is important that X or It is necessary to X, is an evaluative structure without this contrastive focus. Neither splits a simple proposition around one extracted element in the same way.
An it-cleft redistributes emphasis; it does not verify or guarantee the truth of its focus. The writer must supply accurate facts. The construction only organises their presentation.
The printer broke down twice this week.
The printer broke down twice this week.
This is a neutral report. Additional context could justify highlighting twice, for example; the sentence alone does not determine whether a cleft is needed.
It is believed that the printer failure was linked to a power surge.
It is believed that the printer failure was linked to a power surge.
This is anticipatory it with a reporting verb, not a cleft. No single element has been extracted; the whole proposition appears in the postponed clause.
Common mistakes
Incorrect:It was the missing invoice delayed the payment.
Correct:It was the missing invoice that delayed the payment.
When the focused element is the subject of delayed, retain that, or who for a person. Here, that connects the missing invoice to the rest of the cleft.
Incorrect:It was the auditor which flagged the error.
Correct:It was the auditor who flagged the error.
The focus is a person, the auditor, so who is a natural linker. Which does not refer to a person in this pattern.
Incorrect:It were the volunteers that repainted the hall.
Correct:It was the volunteers that repainted the hall.
Be after It is third-person singular, is/was, regardless of the focus's number. Were is incorrect here.
Incorrect:It wasn’t until March that the results was published.
Correct:It wasn't until March that the results were published.
Results is plural within the that-clause, so use were. It wasn't until March means 'only in March'; any implication of lateness comes from context, not until alone.
Incorrect:It that was the finance office who approved the transfer.
Correct:It was the finance office who approved the transfer.
That incorrectly separates It from was. Keep It + be together and put the linker after the focus rather than directly after It.
Incorrect:It the marketing team was that identified the trend.
Correct:It was the marketing team that identified the trend.
Was belongs immediately after It, before the focus rather than after it.