Wh-Cleft Sentences: Standard, Reversed, and Action Focus: correct answers
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A wh-cleft sentence splits a simple sentence into two parts using a *wh-*clause (usually starting with what) and the verb be. The purpose is to put a spotlight on one piece of information — the part you really want the listener to notice.
Take a plain sentence:
I need more time.
Now reshape it as a wh-cleft:
What I need is more time.
The meaning hasn't changed, but the emphasis has. The what-clause ("what I need") sets up a kind of question in the listener's mind, and the second half ("more time") delivers the answer with extra weight.
Three Patterns You Need to Know
Standard wh-cleft — the what-clause comes first:
What surprised me was her honesty.
Reversed wh-cleft — the focused element comes first, and the what-clause follows:
Her honesty was what surprised me.
Both sentences highlight her honesty, but the reversed version sounds more natural in conversation, especially when you're reacting to something someone just said.
Action-focus wh-cleft — when the spotlight falls on an action, use what … do/did … is/was + a bare infinitive or to-infinitive:
✅ What she did was (to) call the police.
This structure emphasises the action itself — calling the police — rather than who did it or when.
Worked Examples and Common Traps
Look at these pairs carefully:
✅ What I like about this city is the architecture. ❌ What I like about this city is like the architecture.
The verb be already connects the two halves. Learners sometimes repeat the main verb after is/was because the sentence feels incomplete — it isn't. The what-clause contains the verb; the second half just names the focused element.
Now an action-focus example:
✅ What he did was resign from the committee. ❌ What he did was resigned from the committee.
After what … did … was, the verb that follows should be a bare infinitive (resign) or to resign — never a past-tense form. The tense is already carried by did and was; doubling it with resigned is the single most frequent mistake at this level.
When to Use (and When Not to Bother)
Wh-clefts work best when you want to correct, clarify, or contrast:
I don't need advice. What I need is practical help.
They also appear constantly in spoken English when someone is explaining or justifying:
What happened was the train got cancelled.
Don't force a wh-cleft when the sentence has no particular focus. "What I ate was breakfast" sounds odd because there's nothing surprising or contrastive about eating breakfast. The structure only earns its place when one element genuinely deserves the spotlight.
Edge Cases Worth Knowing
Plural subjects after what. The verb be can be singular or plural depending on the focused element, but in practice most speakers use a singular verb:
What we need is new ideas. (common, natural) What we need are new ideas. (grammatically strict, rarer)
Both are accepted; exams typically allow either.
Other wh-words. Although what dominates, you'll occasionally meet where, when, or the reason (why):
The reason I'm late is that the bus broke down. Where I feel happiest is at home.
These follow the same logic — wh-clause sets up, be connects, focused element lands.
The thing / All construction. Informal English often replaces what with the thing or all:
The thing is, nobody told me. All I want is a quiet evening.
These are essentially wh-clefts in disguise and behave the same way.
One final reminder: in action-focus clefts, resist the urge to match tenses across both halves. The what-clause carries the tense; the complement after was/is stays in the base form. Get that right and the rest falls into place.
Correct answers
Question 1
Choose the correct phrase to complete the detective's dramatic reveal.
The fingerprints were wiped clean, but what _____ that the security cameras had been disabled exactly two minutes before the heist.
The correct answer is really puzzled the investigators was.
In this wh-cleft sentence, the entire noun clause ("what really puzzled the investigators") acts as a singular subject. Therefore, it requires the singular verb "was".
Even though the word "investigators" is plural, it is the object of the verb "puzzled" inside the clause, not the subject of the main sentence. We use the past tense "was" to maintain agreement with the past narrative of the crime.
Question 2
The correct answers are what, was, and order.
What introduces the pseudo-cleft clause ("what the panicked chef actually did"), which acts as the subject of the sentence.
Was is the singular linking verb. It is in the past tense to agree with the action ("did").
Order is a bare infinitive. In a Wh-cleft sentence that focuses on an action using a form of "do" (e.g., what he did), the emphasized action that follows the verb to be takes the form of a bare infinitive (or sometimes a full infinitive), rather than matching the tense of the main verb.
Question 3
Help Juliet's best friend describe the tragic first date by choosing the correct word for each blank.
Romeo thought he was being incredibly romantic. However, what he actually did was spill hot soup all over Juliet's brand-new dress. What she really wanted at that exact moment was a towel, not a dramatically recited poem!
Romeo thought he was being incredibly romantic. However, what he actually did was spill hot soup all over Juliet's brand-new dress. What she really wanted at that exact moment was a towel, not a dramatically recited poem!
did: In a wh-cleft sentence, the tense in the what-clause must logically align with the main verb. Since the main verb is the past tense "was," we need the past tense "did."
spill: This is a tricky advanced rule! When a wh-cleft focuses on an action (e.g., "What he did was..."), the focused verb takes the form of a bare infinitive (or sometimes a to-infinitive). Even though the sentence is in the past tense, using the past tense "spilled" here is grammatically incorrect.
wanted: Again, the past tense "wanted" is required to match the past tense "was" later in the sentence.
Question 4
The correct answers are All I ever wanted was to retire to a quiet island. and What I have always wanted is to retire to a quiet island.
These are examples of pseudo-cleft sentences used for strong emphasis. You can use What or All (meaning "the only thing") to introduce the subject clause.
"All what" and "the thing what" are classic grammatical errors; what already means "the thing that," so combining them is redundant. Finally, the subject clause "What I want" is treated as singular, so it requires the singular verb is, not are.
Question 5
Help the office manager finish his dramatic email to the lunch thief by choosing the correct word for each blank.
You claim it was an innocent mistake. However, what you forgot to check was the security camera hidden above the microwave. A formal, written apology is what the HR department expects from you by 5 PM. Furthermore, all you actually achieved today was proving that you cannot be trusted with other people's yogurts!
You claim it was an innocent mistake. However, what you forgot to check was the security camera hidden above the microwave. A formal, written apology is what the HR department expects from you by 5 PM. Furthermore, all you actually achieved today was proving that you cannot be trusted with other people's yogurts!
forgot: The past tense "forgot" correctly agrees with the past tense verb "was" that links the two parts of the cleft sentence.
what: This is an inverted wh-cleft sentence. Instead of starting with "What," the focused element ("A formal, written apology") comes first, followed by the "be" verb ("is"), and finally the what-clause. "Which" and "how" do not form pseudo-cleft sentences in this manner.
all: We can use "all" (meaning "the only thing") instead of "what" to form a cleft sentence that adds a slightly different emphasis. "Whole" and "every" are incorrect because they require a following noun (e.g., "every thing").
Question 6
The correct answers are what, What, and is.
what (first gap): This is a reversed Wh-cleft sentence (Focus + be + Wh-clause). "What" functions as a nominal relative pronoun meaning "the thing that." "That" and "which" cannot stand alone without a noun antecedent here.
What (second gap): This introduces a standard Wh-cleft sentence (Wh-clause + be + Focus) to place heavy emphasis on the source of his frustration.
is (third gap): The Wh-clause ("What frustrates me most") acts as a singular subject, so it takes the singular verb "is" to link it to the complement ("the terrible espresso machine").
Question 7
The correct answers are What he did was set the kitchen on fire. and What he did was to set the kitchen on fire.
When a wh-cleft sentence focuses on an action (using the verb do in the wh-clause), the focused element after the verb be must be an infinitive clause. You can use either a bare infinitive ("set") or a to-infinitive ("to set").
Gerunds ("setting") are incorrect here. Additionally, the wh-clause ("What he did") must use normal statement word order, not question word order ("What did he do"), and the linking verb was cannot be omitted.
Question 8
Select the grammatically correct phrase to complete the political journalist's article.
The public assumed the mayor resigned due to the recent embezzlement rumors. However, a sudden loss of support from her biggest donors _____ .
The correct answer is was what actually prompted her sudden exit.
This is an inverted wh-cleft sentence. In a standard wh-cleft, the wh- clause comes first (e.g., "What prompted her exit was a loss of support").
In the inverted version, the focused element ("a sudden loss of support") is moved to the front. It is then followed by the verb "to be" ("was") and finally the wh- clause ("what actually prompted her sudden exit"). Choosing "what actually prompted her sudden exit was" would incorrectly place the verb at the very end, leaving the sentence incomplete.
Question 9
The correct answers are What the butler hid in the grandfather clock was the diamond. and The diamond is what the butler hid in the grandfather clock.
Wh-cleft sentences can be constructed in the standard order (What-clause + be + focused element) or reversed (Focused element + be + what-clause). Both options correctly isolate "the diamond" for dramatic emphasis.
The incorrect options contain structural errors: "What did the butler hide" incorrectly uses question word order inside a noun clause; "the thing what" is non-standard (it should be "the thing that"); and "were" is incorrect because the focused element "the diamond" is singular.