What Part 3 actually tests
Each gap hands you a root like DECIDE and a sentence where “decide” cannot fit — you need decision, decisive, indecisive or decisively. Two separate skills are being checked: do you know the word family, and can you read the sentence well enough to know which member it wants? Most dropped marks come from the second skill — candidates produce a real English word that is the wrong part of speech, or the right one with the wrong sign (positive where the sentence needs negative).
Read the gap first: the part-of-speech clues
The words around the gap tell you what it needs, before you think about the root at all:
| Clue around the gap | The gap probably needs |
|---|---|
| a / the / this + gap + of, or a verb after it | a noun |
| gap directly before a noun | an adjective |
| gap after a full verb phrase, or between commas | an adverb |
| to + gap, or will/should + gap | a verb |
| “Although”, “despite”, “far from” nearby | often a negative form — check the logic |
That last row is the exam’s favourite trap: the sentence logic decides the sign, and it is easy to double-negate. “Far from being ___ (HELP), the instructions confused everyone” takes helpful — “far from” already carries the negation, so unhelpful would say the opposite of what the sentence means. Whenever you spot a negative marker near the gap, slow down and read the whole sentence’s meaning before choosing the sign — this is where Part 3 marks live.
Try it nowRead eight real gaps before touching the rootB2 word-formation exercises — every answer explained, the first two free, no account needed.PractiseThe high-yield noun suffixes
A handful of suffixes cover most noun answers in past papers:
| Suffix | Pattern | Examples |
|---|---|---|
| -tion / -sion | verb → noun | inform → information · decide → decision · permit → permission |
| -ment | verb → noun | develop → development · achieve → achievement · encourage → encouragement |
| -ness | adjective → noun | aware → awareness · fit → fitness · willing → willingness |
| -ity | adjective → noun | able → ability · popular → popularity · responsible → responsibility |
| -ance / -ence | verb/adj → noun | perform → performance · differ → difference · important → importance |
| -er / -or / -ist | person nouns | employ → employer · visit → visitor · science → scientist |
Watch the spelling changes as the suffix attaches: able → ability (the e goes), decide → decision (d becomes s), responsible → responsibility. Part 3 answers must be spelled correctly — a right word spelled wrongly scores nothing.
Adjective suffixes and the opposite pairs
- -ful / -less — the built-in opposites: useful/useless, careful/careless, harmful/harmless. The sentence’s logic picks the side.
- -able / -ible — enjoyable, reliable, incredible, responsible. If the root is a full verb you could use on its own, -able is the safer guess.
- -ive, -ous, -al, -y — attractive, dangerous, traditional, healthy: less predictable, which is why word families are worth learning as families.
Negative prefixes: a guessing heuristic
When the logic demands a negative and you are unsure which prefix the word takes, the odds run like this: un- is the most common in English overall (unhappy, unusual, unlikely); im- goes before m and p (impossible, impatient); ir- before r (irregular, irresponsible); il- before l (illegal, illogical); dis- favours verbs and their families (disagree, dishonest, disappearance); in- takes much of the Latin-flavoured rest (incorrect, invisible, informal). A heuristic, not a law — but it turns a blank guess into a weighted one.
The trap of the unchanged root
Part 3 never wants the root word as printed — if it fitted, there would be nothing to test. If your answer is the root unchanged, you have misread the gap. And in the other direction, remember that some gaps want two changes at once: a prefix and a suffix (employment → unemployment, expected → unexpectedly). If the sentence logic is negative and the gap needs a noun, build both.
A five-item warm-up
Cover the answers below the set; roots in capitals.
- Her ___ to detail makes her a superb editor. (ATTEND)
- The instructions were so ___ that nobody finished. (CONFUSE)
- It was ___ of him to leave without paying. (HONEST)
- The park is within walking ___ of the station. (DISTANT)
- She reacted ___ calmly to the bad news. (SURPRISE)
Answers: attention · confusing · dishonest · distance · surprisingly. If any of the five reasoning steps felt shaky — noun clue, -ing/-ed choice, prefix pick, family spelling, adverb build — that is your pattern to drill.
Learn the patterns here, drill them there
Reference pages build recognition; exercises build speed. The B2 Use of English bank has a full part dedicated to word formation — 60 exercises with every answer explained, the first two free. The neighbouring patterns are covered in the FCE grammar topics guide (transformations live there) and the topic-based vocabulary list; word families also quietly upgrade your essays — see how to write an FCE essay. The whole exam is mapped in the complete B2 First preparation guide.