Why these two belong in one lesson
At B2 you can treat word formation as vocabulary and key word transformations as grammar, and mostly get away with it. At C1 that separation breaks down. A Part 4 item will hand you a key word that is a noun when the sentence needs a verb, or ask you to make a sentence formal and passive in the same rewrite.
Candidates who have drilled the two skills in isolation meet these compound items and freeze, because each half is familiar and the combination is not. That is the whole reason to practise them together.
Part 3: word formation, several steps at a time
Eight gaps, a root word in capitals beside each. This remains the single most improvable part of the paper, because the material is finite — but at C1 the answers reach further.
What “multi-step” actually means
| Root | Answer | Changes needed |
|---|---|---|
| ACHIEVE | unachievable | Verb → adjective (-able), plus a negative prefix |
| RELY | unreliability | Verb → adjective → noun, plus a prefix, plus a spelling change (y → i) |
| CONSIDER | inconsiderate | Verb → adjective, negative prefix, and not the adjective you first thought of (considerable is a different word) |
| STRENGTH | strengthened | Noun → verb → past participle, with no visible affix at the verb stage |
Two traps do most of the damage. The first is form — the gap wants a noun and you supply the adjective, or it wants a plural and you write the singular. Read the words either side of the gap before you look at the root.
The second is meaning, and specifically negatives. A gap frequently needs unlikely where likely would be grammatically perfect, and the only clue is the logic of the sentence. This is where most otherwise-strong candidates lose their Part 3 marks.
Part 4: key word transformations
Six sentences to rewrite so the meaning stays the same, using a given key word, in between three and six words including that key word.
The rules, exactly
- The key word cannot change in any way — no tense, no plural, no derived form. If your answer needs a different form of it, the structure is wrong.
- Three to six words. Contractions count as two, so didn’t is two words and writing it can push you over.
- Two marks per question, split across two halves. A half-right answer scores one, so an incomplete attempt always beats a blank.
The patterns that recur
- Active ↔ passive — especially with reporting verbs: People believe he left → He is believed to have left.
- Direct ↔ reported speech, with the tense shift and the reporting verb both under test.
- Phrasal verb → single formal verb and back: put off ↔ postpone, look into ↔ investigate.
- Set expressions — on the verge of, no sooner… than, it’s high time. These are memorised or they are not there.
- Inversion and cleft — Not until… did he, What surprised me was. C1-only territory.
Where the two skills collide
This is the C1 signature, and it is why the post covers both. Some Part 4 items require a word-formation change inside a structural rewrite:
“He didn’t manage to finish.” with the key word SUCCESS needs you to see that the answer runs through succeed → successful and land on was not successful in finishing — a derivation and a restructuring in one move.
The habit that helps: when a key word looks like the wrong part of speech for the sentence, that is the signal, not an obstacle. Ask what form of it would fit and build the structure around that.
Try it nowRewrite six sentences around the key wordTransformations with the structure named in every explanation — including the compound type. The first is free.PractiseFour worked transformations
Read the key word first and ask what structure it forces. That question, rather than the meaning of the original sentence, is what unlocks most items.
| Original | Key word | Answer | What it turned on |
|---|---|---|---|
| They think the painting was stolen. | BELIEVED | is believed to have been | Passive reporting structure, plus a perfect infinitive for the earlier event |
| I regret not applying for the job. | WISH | wish I had applied | Regret about the past takes the past perfect after wish |
| She only realised her mistake later. | UNTIL | was not until later that she | Cleft with inversion — a C1-only pattern that B2 rarely tests |
| He didn't manage to finish on time. | SUCCESS | was not a success in finishing | Word formation inside the rewrite: the key word is a noun, so the structure has to be built around it |
The last one is the compound type this post exists for. The key word arrives as the wrong part of speech for the sentence, and the temptation is to conclude you have misread it. You have not — that mismatch is the question.
A technique that makes patterns stick
Rewrite the patterns about yourself. Instead of memorising no sooner… than as an abstract structure, write “No sooner had I started studying than my phone rang”. Structures attached to something true are recalled far more reliably under exam pressure than ones attached to a textbook sentence about someone called John.
Keep them in one list and reread it, rather than doing more exercises. Both these parts reward recognition speed, and recognition comes from rereading, not from volume.
Practising it
Do three or four of one task type in a row rather than one of each. What you are learning is what the task rewards, and that only becomes visible across repetitions — a single exercise of each teaches almost nothing.
Part 3 word formation and Part 4 key word transformations both come with an explanation for every answer, and the first exercise in each is free. For where these sit in the paper as a whole, see all eight R&UoE parts explained, or start from the C1 Advanced exam preparation guide.