Mastering It-Cleft Sentences: Agreement and Adverbials: correct answers
Jump to answers ↓An it-cleft sentence takes a single idea and splits it into two clauses to put a spotlight on one piece of information. The basic frame is:
It + be + focused element + that/who/which clause
Take an ordinary sentence: Maria fixed the printer on Monday. You can cleft it several ways depending on what you want to emphasize:
- It was Maria who fixed the printer on Monday. (focus on the person)
- It was the printer that Maria fixed on Monday. (focus on the object)
- It was on Monday that Maria fixed the printer. (focus on the time)
Notice that the rest of the sentence — everything that isn't spotlighted — goes into the clause after that/who/which. The structure itself isn't hard, but two areas cause real trouble at B1–B2 level: subject–verb agreement and clefting adverbials.
Agreement: which verb agrees with what?
The verb be after it agrees with the tense and context, not with the focused element. It is always singular, so you write it was, it is, never it were (unless you're in a subjunctive context, which is rare here). That part is straightforward.
The trickier agreement happens inside the relative clause. Look at these two sentences:
✅ It is the students who are responsible for the project. ❌ It is the students who is responsible for the project.
The verb in the relative clause (are) must agree with the focused noun (the students), not with it. Many learners automatically write is because their eye is still on It is… at the start. Train yourself to look at the noun right before who/that — that noun controls the verb that follows.
One more pair to compare:
✅ It was I who was late. (formal; some speakers accept who were late by analogy with I were in subjunctive, but in standard clefts, was is normal) ❌ It was me who were late.
In everyday English you'll hear It was me who was late, with the object pronoun. Exams and formal writing prefer I, but either way the relative-clause verb stays was because the reference is to a single person.
Clefting adverbials
You can focus not just on nouns but on adverbial phrases — of time, place, reason, or manner. When you do this, the connector is almost always that, not when, where, or why:
✅ It was in 1969 that humans first landed on the Moon. ❌ It was in 1969 when humans first landed on the Moon.
The when version feels logical ("1969 is a time, so use when"), and that's exactly why so many learners choose it. But in a standard it-cleft the relative word is that — or you can drop it entirely: It was in 1969 humans first landed on the Moon. The same principle applies to place and reason:
✅ It was at the café that we met, not at the library. ❌ It was at the café where we met.
The mistake to watch for
The single most common error is mixing up two jobs at once: using when/where inside an it-cleft and breaking agreement. A sentence like It is on weekends when the shops is crowded has both problems. Fix it in two steps: switch when → that, then check agreement (the shops → are):
✅ It is on weekends that the shops are crowded.
A quick self-check
Before you move on to the quiz, try clefting this sentence three different ways — focusing on the person, the object, and the time:
Tom sent the email yesterday.
If you got It was Tom who sent the email yesterday, It was the email that Tom sent yesterday, and It was yesterday that Tom sent the email, you're ready.
Correct answers
Question 1
The correct answers are It was because the lead actor forgot his lines that the audience started laughing. and It was the collapsing scenery, rather than the bad acting, that ultimately ruined the show.
It-clefts use that to connect the emphasized focus to the rest of the sentence.
Even when emphasizing a reason ("because..."), you must use that, not why. Similarly, what is never used as the relative pronoun in a standard it-cleft sentence (though it is used in wh-clefts, such as "What ruined the show was the scenery").
Question 2
The correct answers are It, am, and have.
Cleft sentences must always begin with the dummy pronoun it, regardless of whether the emphasized noun is singular or plural.
In formal English, when the emphasized part is a subject pronoun ("I", "you"), the verb in the relative clause must agree with that specific pronoun. Therefore, the relative pronoun "who" takes am to agree with "I", and have to agree with "you".
Question 3
The correct answers are It is I who am taking full responsibility for the incident. and It was the marketing team that left the milk out overnight.
In formal it-cleft sentences, the verb in the relative clause must agree with the emphasized subject. Because the subject is I, the correct verb is am (not is).
Furthermore, when the emphasized noun phrase functions as the subject of the relative clause (the marketing team left the milk out), you must use that or who, never the object pronoun whom.
Question 4
Help the kingdom's chief gossipmonger set the record straight about the latest royal scandal.
The rumors claim the King gave the dragon to the Duke, but it was actually _____ he gifted the fire-breathing beast!
The correct answer is to the Duchess that.
In a cleft sentence, if the original verb requires a preposition (e.g., "gifted [something] to [someone]"), that preposition must either stay at the end of the relative clause or move with the focused noun.
Because the sentence ends with "he gifted the fire-breathing beast!" (missing the preposition "to"), the preposition must be included in the focus: It was to the Duchess. When a prepositional phrase is the focus of a cleft sentence, we use that to introduce the relative clause.
Question 5
The correct answers are It was not until midnight that the thief bypassed the security cameras. and It was from the hidden safe that the diamond was actually stolen.
In an it-cleft sentence emphasizing a prepositional phrase (like from the hidden safe), the relative clause must be introduced by that, not where or when.
Additionally, the distractor "did the thief bypass" incorrectly mixes an it-cleft with negative inversion. You can either use an it-cleft ("It was not until midnight that the thief bypassed...") or negative inversion ("Not until midnight did the thief bypass..."), but never both at the same time!
Question 6
Complete the dramatic chef's explanation of a culinary disaster by choosing the correct word for each blank.
"It was because the main oven suddenly malfunctioned that the delicate cheese soufflé collapsed. Furthermore, it was to my senior assistant that I had explicitly handed the timer, so he is entirely to blame!"
"It was because the main oven suddenly malfunctioned that the delicate cheese soufflé collapsed. Furthermore, it was to my senior assistant that I had explicitly handed the timer, so he is entirely to blame!"
was: This forms the standard "It was... that" cleft structure in the past tense.
that: When focusing on an entire "because" clause in an it-cleft, the clause must be followed by "that". Many learners incorrectly use "why" here.
to: We "hand something to someone." In a cleft sentence, the preposition stays with the noun phrase when it is moved into the focus position (It was to my assistant that...).
Question 7
Complete Dr. Aris's dramatic lab journal entry about his recent mishap.
It was not until the purple smoke filled the entire laboratory _____ realized I had mixed up the baking soda and the highly reactive unobtainium.
The correct answer is that I.
In an it-cleft sentence focusing on a time phrase (especially with "not until"), the relative clause must be introduced by that.
While "when" might sound tempting because it refers to time, cleft sentences rely on "that" to connect the focused element to the rest of the clause. "Did I" would only be used if the sentence started with negative inversion (Not until the smoke filled the lab did I realize...).
Question 8
The correct answers are must have been and that.
In an it-cleft sentence, we use the relative pronoun that (not where or which) to connect the emphasized phrase to the rest of the sentence, even when emphasizing a prepositional phrase of place like "through the open skylight."
Additionally, must have been is the correct modal perfect form to express a strong logical deduction about a past event.
Question 9
Help the theatrical ghost hunter complete her spooky field report by choosing the correct word for each blank.
"It was only after the candles mysteriously blew out that the phantom finally made its presence known. Furthermore, it was the skeptical cameraman, not the psychic, who fainted first!"
"It was only after the candles mysteriously blew out that the phantom finally made its presence known. Furthermore, it was the skeptical cameraman, not the psychic, who fainted first!"
was: The past tense "was" is required to match the past tense verbs in the rest of the sentence ("blew out", "made", "fainted").
that: In an it-cleft sentence focusing on an adverbial time phrase, we must use the relative pronoun "that" to connect the clauses. Using "when" is a very common mistake!
who: The cameraman is the subject of the verb "fainted," so the subject relative pronoun "who" is correct.
Question 10
Complete the project manager's slightly accusatory email regarding the disastrous new company mascot.
Please stop blaming the marketing interns; it is I who _____ responsible for approving the giant neon platypus.
The correct answer is am.
In an it-cleft sentence where the focused element is a subject pronoun ("I"), the verb in the relative clause must agree with that pronoun.
Even though "who is" sounds very natural in casual speech, formal grammar requires the verb to match "I" (I am -> It is I who am).