Consider this gap:
The committee treated the early figures as ______ because several invoices had not yet been checked. PROVISION
Both provisional and provisionally belong to the family, but only the adjective can follow as and describe figures. The unfinished invoice check supplies the meaning: the figures exist as the current set, but they are not final.
That combination—sentence slot, family form, and contextual meaning—drives Cambridge C2 Proficiency Reading and Use of English Part 3, Word formation. Cambridge’s current format gives a text with eight gaps. A stem appears beside each gap and must be changed to form the missing word. The task focuses particularly on affixation, internal changes, and compounding. Each correct answer receives one mark.
For the wider exam route, use the Cambridge C1/C2 vocabulary hub and the Exam English hub.
Decide in five passes
Do not start by attaching the first familiar suffix to the stem. Use five checks:
- Slot: Does the grammar require a noun, verb, adjective, or adverb?
- Polarity: Does the sentence need the positive or negative member of the family?
- Meaning: Which family member makes the claim precise?
- Collocation: Does the completed phrase sound natural around the gap?
- Spelling: Does the transformation change more than the final suffix?
The entire text matters. A local phrase may allow two grammatical forms, while the previous sentence makes only one meaning coherent.
Six families and their boundaries
Prevalent and prevalence
The adjective prevalent marks something as occurring widely or commonly within a group, place, field, or period: prevalent among commuters; prevalent in the sector. Prevalence is the corresponding noun: the prevalence of remote work.
Do not treat prevalent as predominant. Something can be common without being the single main option. The word also does not claim that a trend is universal.
Provisional and provisionally
Provisional marks something already granted, produced, agreed, or in effect temporarily because a defined confirmation step remains: provisional figures pending audit. Provisionally is the adverb: provisionally accepted.
It is not simply a grander form of tentative. Tentative can mark an arrangement that is not yet firmly decided. Provisional more naturally points to a current temporary status and an outstanding step. Context, not prestige, chooses the word.
Substantial and substantially
Use substantial for an amount, degree, or extent that is large or important: a substantial reduction; substantial evidence. Substantially modifies a verb, adjective, or clause: costs fell substantially.
It does not automatically mean statistically significant, permanent, or decisive. Insubstantial can mean lacking solidity, importance, or adequate basis, but a negative prefix must be licensed by the sentence.
Negligible and negligibly
Negligible means so small or unimportant that it is not worth serious consideration in that context: a negligible difference. The rare adverb negligibly can modify a change: performance improved negligibly.
Negligible does not mean literally zero. If the text reports a tiny measurable difference, negligible can still fit. Do not confuse it with negligent, which describes a failure to take proper care.
Understanding is only the first step.
Lyra Practice helps you retrieve and use high-value workplace expressions in realistic situations until they feel natural.
Start a practice session →Corroborate and corroboration
To corroborate a claim, account, or finding is to strengthen it with additional evidence, often from an independent source. Corroboration is the noun. Corroborated and uncorroborated are participial adjectives when the context requires supported or unsupported status.
The object is a claim-like proposition, not normally a person: records corroborate a witness’s account, not simply the witness. Corroborate need not mean prove beyond all doubt.
Conducive and conducive to
Conducive means tending to create conditions that help a result occur. The productive frame is conducive to + noun or gerund: conditions conducive to concentration; a schedule conducive to working carefully.
It does not say the condition guarantees the result. A quiet room may be conducive to concentration even if one participant remains distracted. The fixed preposition is part of the lexical decision.
Worked eight-gap text
This is original practice, not Cambridge exam material. Each answer is controlled by grammar and the surrounding meaning.
A library tests quiet study zones
A university library reviewed noise reports from three floors. Complaints were especially (1) ______ near the group-work rooms, where conversations could be heard from the silent area. PREVAIL
The library then introduced a (2) ______ seating plan for four weeks, pending a fire-safety review of the new partitions. PROVISION
During the trial, reported interruptions fell (3) ______, from an average of twelve per day to four. SUBSTANCE The difference in desk occupancy, however, was (4) ______: the average changed by less than one percentage point. NEGLECT
Door-counter data provided independent (5) ______ of students’ reports that the quiet floor remained busy. CORROBORATE However, one claim—that every complaint came from the group rooms—was still (6) ______, because several reports did not identify a source. CORROBORATE
Students said the clearer signs and enclosed spaces were more (7) ______ to sustained concentration. CONDUCE The panel therefore recommended keeping the layout, while noting that the evidence for a building-wide redesign remained (8) ______. SUBSTANCE
Answer key: slot, form, meaning
| Gap | Answer | Controlling evidence |
|---|---|---|
| 1 | prevalent | The gap follows especially and describes complaints; an adjective meaning common is required. |
| 2 | provisional | The adjective modifies seating plan, and the named safety review is the outstanding formal step. |
| 3 | substantially | The gap modifies fell, so the adverb is required; the stated fall is large. |
| 4 | negligible | An adjective follows was; the measured change of under one point licenses “too small to matter here,” not zero. |
| 5 | corroboration | Provided independent requires a noun; door data supplies additional evidence for an existing report. |
| 6 | uncorroborated | The passive-like adjective follows was still; the following clause says evidence is missing, so negative polarity is required. |
| 7 | conducive | The adjective is completed by the fixed frame conducive to + noun. It marks helpful conditions, not a guarantee. |
| 8 | insubstantial | The adjective follows remained; the limited trial does not provide an adequate basis for the much broader redesign claim. |
The same stem appears twice at gaps 5–6 and 3–8 so that suffix recognition alone cannot solve the text. The noun corroboration names supporting evidence; uncorroborated labels a claim whose support is missing. Substantially reports the size of one observed fall; insubstantial evaluates the evidential basis for a wider proposal.
Why the whole text controls the answer
At gap 4, small would fit the broad meaning, but the supplied family is NEGLECT. Negligible is licensed because the exact difference is under one percentage point. It would be unsafe to infer zero, and negligent would wrongly describe careless behaviour.
At gap 6, corroborated is grammatically possible after was still. The next clause defeats it: several reports lack a source, so the universal claim has not received the additional support it needs. The negative prefix is a meaning decision, not decoration.
At gap 8, the text does not say the trial itself was insubstantial. It says the evidence is too limited for a building-wide redesign. Scope matters: evidence can support a local decision without supporting a broader one.
Affix, internal change, and spelling checks
Build a small family grid, but record only forms that English actually uses:
| Stem/family | Noun | Adjective | Adverb/verb |
|---|---|---|---|
| PREVAIL | prevalence | prevalent | prevail |
| PROVISION | provision | provisional | provisionally |
| SUBSTANCE | substance | substantial / insubstantial | substantially |
| NEGLECT | neglect / negligence | negligible / negligent | negligibly / neglect |
| CORROBORATE | corroboration | corroborated / uncorroborated | corroborate |
| CONDUCE | — | conducive | — |
This is not a promise that every member will fit whenever its part of speech fits. Negligent difference is grammatical in shape but wrong in meaning. Conducive also needs its normal to frame. Treat spelling and collocation as separate checks.
Common Part 3 errors
- Choosing a sophisticated noun before identifying the sentence slot.
- Adding un- merely because the paragraph contains a problem.
- Reading negligible as exactly zero or confusing it with negligent.
- Treating prevalent as proof that something is predominant or universal.
- Calling figures provisional without an existing temporary set or a defined next step.
- Using corroborate with a person rather than the person’s account or claim.
- Writing conducive for when the taught frame requires conducive to.
- Assuming substantial proves causation, permanence, or statistical significance.
- Inventing a family member because a familiar suffix looks possible.
- Solving each line in isolation and missing a polarity clue in the next sentence.
Quick controlled practice
Complete each sentence with a form of the capitalized prompt.
- The difference between the two totals was ______: less than one tenth of one percent. NEGLECT
- Visitor records offered independent ______ of the organizer’s attendance estimate. CORROBORATE
- The revised rota was introduced ______ while the manager checked leave requests. PROVISION
- Clear responsibilities can create conditions ______ to faster decisions, although they do not guarantee them. CONDUCE
- The report found that the practice was increasingly ______ among smaller firms, but not dominant. PREVAIL
- Response times improved ______ after the form was shortened. SUBSTANCE
Answers: negligible, corroboration, provisionally, conducive, prevalent, and substantially. The clues are respectively scale, noun slot plus independent evidence, adverb slot plus temporary status, the fixed to frame, widespread rather than dominant, and an adverb modifying improved.
Fresh practice
Write a coherent 120-word text about a short pilot project. Add eight gaps and stems. Include one adjective/adverb contrast, one positive/negative polarity contrast, one form with a spelling change, and one collocation that extends beyond the gap. For every answer, annotate slot, polarity, meaning, collocation, and spelling. If two answers remain equally defensible, add contextual evidence rather than declaring one synonym wrong.
Sources
- C2 Proficiency exam format — Cambridge English
- C2 Proficiency preparation and sample tests — Cambridge English
- C2 Proficiency handbook for teachers — Cambridge English
Related
- Cambridge C1 Word Formation: Build the Right Form
- Cambridge C2 Vocabulary Precision Beyond C1
- Cambridge C2 Open Cloze: Grammar and Fixed Phrases
- Cambridge C2 Part 1: Collocations and Shades of Meaning
Lyra Practice is not affiliated with or endorsed by Cambridge University Press & Assessment.