Where it appears in the exam
What is it?
Reference words stand in for something already said so you do not have to repeat it: this, that, these, those, such, one/ones, the former/the latter. They add no new information — they point backwards. Their value is the thread they create between sentences, and that thread is what holds a text together.
Why it matters in the exam
This is the competency in the family with the widest real presence in the exam, along three different routes. It is tested as a Part 1 item in the such/so pair, the only one in the family with four options set against each other; it is filled in as a one-word gap in Part 2 — «that of», «one» —; and above all it is the instrument that solves Part 6: nearly every sentence you have to insert contains a word pointing at the paragraph before.
The cognitive trap
"The instinct: placing the intensifier inside the noun phrase ('a so difficult decision') and reaching for one all-purpose word to sum up whole ideas."
Why your brain does this: most languages have a single flexible way of intensifying and a single pronoun for summarising, and neither carries structural restrictions. English splits the work across several words that are not interchangeable, and puts 'such' in a position your first language probably does not use.
It was such a difficult decision… · This explains the delay. · the climate of the north and that of the south
The English rule: such goes before the article, this and that are separated by closeness and attitude, and comparisons demand that/those of. How it matters in the exam: Cambridge offers all of them as options in Part 1 and hides the right one inside Part 6.
Recognition pattern
In the exam, look for the key signal first. The answer follows.
What gives each form away
It was <strong>such</strong> a difficult decision. · <strong>So</strong> difficult a decision exists, but it is literary.
The decision was <strong>so</strong> difficult that she postponed it.
<strong>such</strong> difficult decisions · <strong>such</strong> heavy rain
The population of Madrid is larger than <strong>that</strong> of Seville.
My laptop broke, so I bought a new <strong>one</strong>.
My laptop broke, so I took <strong>it</strong> to be repaired.
Sales fell for three quarters. <strong>This</strong> forced a change of strategy.
She studied law and medicine; <strong>the latter</strong> proved more useful.
The five that recur most
It was a such difficult decision.
Transferred from languages that keep the intensifier inside the noun phrase.
It was such a difficult decision.
Fixed order: such + a/an + adjective + noun. 'Such' comes before the article.
There was such a heavy rain that the match was cancelled.
The article is surplus. Same error in 'such a good news' and 'such an interesting information'.
There was such heavy rain that the match was cancelled.
'Rain' is uncountable, so 'such' takes no article.
Sales fell sharply. It forced a change of strategy.
'It' looks for a specific noun to attach to; to pick up a whole idea, 'this' or 'that' are far clearer, and that is what formal written English expects.
Sales fell sharply. This forced a change of strategy.
'This' can sum up an entire preceding sentence and act as the subject of the next.
The population of Madrid is larger than Seville.
This compares a population to a city. It is understandable, but it is exactly the slip Part 5 turns into a distractor.
The population of Madrid is larger than that of Seville.
'That of' replaces 'the population of' and keeps the comparison between like and like.
This findings suggest a different explanation.
English marks number on the demonstrative itself, which many languages do not, so the agreement gets lost in transfer.
These findings suggest a different explanation.
'Findings' is plural, so the demonstrative agrees: these.
Why your brain gets it wrong
The learner's short circuit
Analyse the trap by exam format
…The council rejected the proposal outright, calling it unrealistic and poorly costed. ______ Within weeks, however, three neighbouring towns had adopted almost identical schemes.
In Part 6 every option is on the same topic — they are written that way on purpose. The brain looks for thematic coherence, which is exactly what fails to discriminate, and settles on whichever option 'sounds related'. The real clue is smaller and far safer: a word pointing backwards only fits if its antecedent sits right before the gap.
unrealistic and poorly costed → Such criticism
Before reading the whole text, underline the reference word in each option: such, this, these, the former, one, another. Then hunt for its antecedent in the paragraphs. An antecedent that does not exist eliminates the option with no argument.
→ Choosing by REFERENCE: 'Such criticism…' requires criticism immediately before
Part 6 is not solved by understanding, it is solved by linking
Part 6 distractors are deliberately on-topic. If your criterion is 'it's about the same thing', you have seven valid options and no reason to choose.
Strategy
Turn each option into a question: what does this sentence require to have already been said? A reference with no antecedent is an option eliminated, and three or four usually fall at once.
It was 4 a difficult decision that she postponed it for weeks.
Both words intensify identically, so meaning separates nothing. What separates them is the shape of what follows: 'such' takes a noun phrase (a difficult decision) and 'so' takes a bare adjective (so difficult). The 'a' in the sentence closes the decision on its own.
This is not a choice of meaning
'So' and 'such' intensify in exactly the same way. The only difference is syntactic, which is why thinking about what they mean does not help: look at what follows the gap.
Strategy
One-glance rule: if there is an 'a' or 'an' after the gap, it is such. If there is a bare adjective, it is so. You do not need the rest of the sentence.
She had left her laptop at home, but a colleague lent her ______ for the afternoon.
«It» is the default pronoun for anything already mentioned, and the laptop has just been mentioned. But what she is lent is not HER laptop: it is another one of the same kind. The brain follows the thread of the topic and never asks whether the object is the same object.
left her laptop at home
Her own laptop stayed at home, so the one she is lent has to be a different one. «It» points at the same item; «one» points at another of its kind. The sentence says hers was unavailable: that is the clue.
→ one
Same object, or same kind of object
This is the distinction no single-pronoun system marks: it = that exact one, one = another like it. In Part 2 there are no options to compare, so the default pronoun comes out.
Strategy
Before writing «it», ask whether you mean the very item you just named. If the sentence explains that it was unavailable, the answer is «one».
Demonstratives & reference (this/that/such) is 1 of 82
The exam tests 82 grammar competencies across 19 families. Mastering one is the first step. Automating all 82 is passing.
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