Casa ESL · C2 Mastery · Teacher's Resource
Answer Key Booklet
All 20 units · Steps 1 & 2 · For teacher use only. Do not distribute to students.
Step 1 — Units 1–10
Unit 01
Epistemology
Exercise 11. Not until the final chapter does the author reveal her thesis. · 2. Rarely has a single paper generated such controversy. · 3. Had we examined the data more carefully, the error would have been apparent. · 4. Under no circumstances should these results be taken as conclusive. · 5. So compelling was the argument that even the sceptics were persuaded.
Exercise 21. At no point did · 2. Were · 3. No sooner · 4. Such · 5. were
Reading1. Rationalists held that truths can be known through reason alone (a priori), while empiricists maintained all knowledge derives from sensory observation. · 2. Some philosophers have abandoned seeking definitive answers and instead evaluate beliefs by their practical consequences rather than correspondence to external reality.
Unit 02
Sociolinguistics
Exercise 11. Language acquisition occurs at a significantly accelerated rate in children compared to adult learners. · 2. Speakers modulate their linguistic behaviour in accordance with the social context and the interlocutors involved. · 3. The findings indicate that socioeconomically disadvantaged populations experience disproportionate inequity. · 4. The precise mechanisms underlying language attrition remain insufficiently understood. · 5. Digital communication practices may be exerting a deleterious influence on the written proficiency of younger demographics.
Exercise 21. get rid of → eliminate / eradicate · 2. a lot of → a substantial number of · 3. look at → examine / analyse · 4. go up → increase / escalate · 5. deal with → address / contend with
Reading1. It served as a prestige dialect that conferred automatic authority on its speakers and functioned as a mechanism of social gatekeeping based on class and education. · 2. Attitudes are becoming more tolerant, especially among younger generations, and code-switching is increasingly seen as sociolinguistic competence rather than inauthenticity.
Unit 03
Economic Theory
Exercise 11. thereby · 2. Owing to · 3. whereby · 4. so much so that · 5. On account of
Exercise 21. thereby · 2. Owing to · 3. whereby · 4. so much so that · 5. On account of
Reading1. Cutting expenditure during a recession reduces aggregate demand, whereby economic contraction deepens and tax revenues decline further, potentially increasing the debt burden. The passage uses "whereby" and "so much so that." · 2. On account of the sheer number of variables involved, it is extraordinarily challenging to isolate specific causal mechanisms in macroeconomic contexts.
Unit 04
Postmodern Literature
Exercise 11. Verbal irony / sarcasm · 2. Structural ambiguity · 3. Dramatic irony · 4. Pragmatic inference / implicature · 5. Litotes / understatement
Exercise 21. The speaker considers the novel overreaching or unsuccessful, despite its grand scope. · 2. The speaker is irritated and is implying the person has overstepped boundaries. · 3. The speaker implies that reports are usually submitted late. · 4. The presentation was terrible, and the speaker is ironically noting the only positive outcome. · 5. The speaker considers the writing style unusual or poor, and the hesitation signals a diplomatic criticism.
Reading1. The realist novel offers a transparent view of a coherent world, whereas the postmodern text is self-referential and contradictory, reflecting back on its own construction rather than presenting a straightforward reality. · 2. The reader must infer meaning from gaps, inconsistencies, and what is left unsaid — focusing on the distance between the narrator's assertions and the evidence, rather than taking the narrator at face value.
Unit 05
Constitutional Law
Exercise 11. shall · 2. Notwithstanding · 3. null and void · 4. Pursuant to · 5. hereinafter
Exercise 21. shall → is required to / must · 2. notwithstanding → despite / regardless of · 3. pursuant to → in accordance with · 4. hereinafter → from now on referred to as · 5. indemnify → compensate / protect against loss
Reading1. Legal English aims for precision to eliminate ambiguity, yet its conventions (archaic vocabulary, complex syntax, passive voice) render texts impenetrable to non-specialists, thereby excluding the very people governed by the law. · 2. That legal precision and accessible prose are not incompatible — statutes and contracts can be both unambiguous and comprehensible to ordinary readers.
Unit 06
Evolutionary Biology
Exercise 11. This gene appears to be strongly associated with the disease, though the precise causal mechanism remains to be fully elucidated. · 2. Available evidence suggests that climate change may have been a significant contributing factor in the species' extinction. · 3. Epigenetic findings appear to complicate, if not challenge, certain aspects of the traditional central dogma. · 4. Our findings are consistent with the theory and lend further support to its central claims. · 5. While genetic factors account for a substantial proportion of observed variation, environmental and epigenetic influences likely play a non-trivial role.
Exercise 21. strongly suggest · 2. is conceivable · 3. Given · 4. appear to · 5. does not yet
Reading1. Because evolutionary biology deals with deep time and fragmentary evidence; hedging calibrates claims to the actual strength of the evidence, making it a mark of scientific precision rather than weakness. · 2. The distinction is epistemological, not merely stylistic — it reflects different degrees of evidentiary support. "Suggests" indicates the evidence is compatible but not conclusive, while "demonstrates" implies much stronger proof.
Unit 07
Geopolitics
Exercise 11. a robust exchange of views → a heated argument · 2. collateral damage → civilian casualties · 3. the situation is fluid → it is chaotic and unpredictable · 4. we urge restraint → stop the violence immediately · 5. not without its challenges → very difficult / problematic
Exercise 21. We have noted with concern certain actions that appear inconsistent with established international norms. · 2. While the talks did not yield the outcomes all parties had hoped for, they provided a useful foundation for further dialogue. · 3. We appreciate the spirit in which the proposal was offered, though we believe it may benefit from further refinement before it can command broad consensus. · 4. We encourage our partners to strengthen institutions of governance and enhance transparency in public administration. · 5. We reserve the right to take all necessary measures to protect our interests should the current situation not be resolved through peaceful means.
Reading1. Strategic imprecision means deliberately obscure language that communicates positions without full commitment. It is functional because it preserves ambiguity as a strategic resource, allowing states to signal positions while retaining room to manoeuvre. · 2. The spectrum runs: "expressed concern" (mildest) → "serious concern" → "grave concern" → "condemnation" (strongest), with each gradation signalling a precise degree of diplomatic disapproval.
Unit 08
Philosophy of Language
Exercise 11. Declarative speech act · 2. Commissive speech act · 3. Directive speech act · 4. Expressive speech act · 5. Declarative speech act
Exercise 21. resign · 2. pledge · 3. pronounce · 4. undertakes · 5. acknowledge
Reading1. Constatives describe the world and can be true or false, while performatives do not describe but enact — they bring states of affairs into being through the utterance itself and can only succeed or fail. · 2. Because the felicity conditions are not met — the speaker lacks the requisite authority (being a judge), and the correct institutional procedures are not in place, so the performative utterance fails.
Unit 09
Cognitive Psychology
Exercise 11. A (anaphoric — "these" refers back to "surprising results") · 2. C (cataphoric — "this" points forward to the discovery) · 3. A (anaphoric — "the former/latter" refer back to the two systems) · 4. C (cataphoric — "what follows" points forward to the analysis) · 5. A (anaphoric — "none" refers back to "several hypotheses")
Exercise 21. The study proved compelling, primarily because its findings challenged the prevailing theoretical framework. · 2. The experiment they conducted demonstrated that memory is considerably less reliable than commonly assumed. · 3. Cognitive load plays a critical role in learning, as excessive demands on working memory impair the encoding of new information. · 4. Metacognitive ability varies considerably among individuals: some demonstrate acute self-awareness in their reasoning, while others show markedly less capacity for such reflection. · 5. The brain relies on heuristics — mental shortcuts that enable rapid decision-making, albeit at the occasional cost of accuracy.
Reading1. The chain is: working memory → capacity → cognitive load → learning → schemas → processing demands. Each term connects to the previous one, sustaining a continuous thematic thread through the paragraph. · 2. Anaphoric references ("this limitation," "such impairment") point backward to previously stated concepts, while cataphoric reference ("specifically") points forward, signalling that a more detailed explanation will follow.
Unit 10
Climate Science
Exercise 11. correlates positively with · 2. strong inverse relationship · 3. is ... attributable to · 4. exhibited ... trajectory · 5. associated ... established
Exercise 21. CO2 concentration correlates positively with global temperature. · 2. There is an inverse relationship between ice cover and sea level. · 3. A weak to moderate positive correlation was observed. · 4. X is associated with Y, though causation has not been established. · 5. Emissions exhibited a sharp upward trajectory before plateauing.
Reading1. It is the strongest certainty term in the IPCC lexicon, a departure from more cautious language. It is supported by converging evidence: strong CO2-temperature correlation, inverse ice-temperature relationship, and paleoclimate records showing unprecedented CO2 levels. · 2. To illustrate the precision of scientific language: the phrasing acknowledges that while human influence is the primary driver, natural variability also contributes, so claiming humans caused ALL warming would be an overclaim.
Step 2 — Units 11–20
Unit 11
Translation Studies
Exercise 11. thrifty / miserly → thrifty (positive: prudent) vs miserly (negative: mean) · 2. confident / arrogant → confident (positive: self-assured) vs arrogant (negative: overbearing) · 3. curious / nosy → curious (positive: inquisitive) vs nosy (negative: intrusive) · 4. vintage / outdated → vintage (positive: classic) vs outdated (negative: obsolete) · 5. determined / stubborn → determined (positive: resolute) vs stubborn (negative: inflexible)
Exercise 21. A deep emotional state of melancholic longing for something or someone absent — English has no single word that captures both the sweetness and pain of this nostalgia. · 2. A quality of cosiness and convivial warmth — while often translated as "cosiness," hygge encompasses a broader cultural concept of comfortable togetherness that "cosy" alone does not capture. · 3. The act of acquiring books and letting them pile up unread — English requires an entire phrase to express what Japanese captures in a single compound word. · 4. Pleasure derived from another's misfortune — English borrowed the German word directly because no native equivalent existed, illustrating a lexical gap. · 5. A form of extraordinary determination and inner strength in the face of adversity — it goes beyond mere "grit" or "resilience" and is bound up with Finnish cultural identity.
Reading1. Connotation, register, rhythm, cultural resonance, and untranslatable concepts — the layers of meaning shaped by culture and history that go beyond literal, factual content. · 2. Domestication makes the text feel native but erases the otherness of the source culture; foreignisation preserves cultural strangeness but at the cost of fluency. Neither is inherently superior.
Unit 12
Rhetoric & Persuasion
Exercise 11. Antithesis · 2. Tricolon · 3. Chiasmus · 4. Anaphora (with tricolon) · 5. Antithesis
Exercise 21. impractical, unaffordable, and unnecessary · 2. despair ... hope (or similar balanced contrast) · 3. courage ... conviction ... compassion (or similar anaphoric pattern) · 4. the size of the fight in the dog · 5. by ... for
Reading1. Both use repetition, but to opposite emotional effects: King builds hope by expanding the scope of his dream with each iteration, while Churchill builds defiance through relentless repetition of resolve. · 2. They exploit the brain's preference for pattern and then deliver surprise within that pattern — combining structural predictability (rhythm the ear anticipates) with semantic force (meaning that moves the mind).
Unit 13
Medical Ethics
Exercise 11. demonstrates · 2. suggest · 3. implies · 4. inferred · 5. indicate
Exercise 21. The data imply a correlation. · 2. The results demonstrate a clear benefit. · 3. Early results suggest a trend toward improvement. · 4. The researcher infers from the data. · 5. The pattern implies a genetic component.
Reading1. Overstating evidence ("demonstrates" instead of "suggests") may lead to premature adoption of unproven treatments; understating it ("suggests" instead of "demonstrates") may delay implementation of life-saving therapies. · 2. A radiograph implies (conveys indirectly) that a fracture may be present; the radiologist infers (concludes) from the image that the bone is broken. The image is an artefact, not an agent — it cannot infer.
Unit 14
Architecture Theory
Exercise 11. palimpsest · 2. organic architecture grows from its site · 3. face (or: public expression / first sentence) · 4. rhythm, proportion, harmony, and structure · 5. we consider that buildings must also serve emotional, cultural, and aesthetic needs that machines do not
Exercise 21. A mixed metaphor (symphony → bones → engine) · 2. A house does not grow with its inhabitants the way a crab changes shells · 3. Anthropomorphising — attributing human qualities to an inanimate entity · 4. It shifts metaphorical frame mid-paragraph (book → meal) · 5. We consider that architecture did not give birth to other art forms in any literal developmental sense
Reading1. It maps linguistic elements (phonemes, grammar, meaningful utterances) onto architectural elements (columns, walls, principles of arrangement), and extends the analogy to include grammatical correctness without meaning and poetic rule-breaking. · 2. The metaphor fails to account for the spatial/simultaneous nature of architectural experience (vs. sequential language), and for the embodied, phenomenological dimension — physical sensations of stone, light, and spatial scale.
Unit 15
International Finance
Exercise 11. The sharp depreciation of the currency · 2. The acquisition of the company was followed by its restructuring. · 3. The failure of regulators to intervene resulted in market destabilisation. · 4. The loss of investor confidence was attributable to a lack of transparency on the part of the bank. · 5. The securitisation of the loans facilitated their subsequent sale to investors.
Exercise 21. regulate → regulation · 2. divest → divestiture · 3. amortise → amortisation · 4. capitalise → capitalisation · 5. deleverage → deleveraging
Reading1. By converting actions into abstract nouns and obscuring agency, nominalisation naturalises policy decisions, making deliberate choices appear as inevitable, impersonal outcomes rather than decisions made by specific actors. · 2. It shows that a single nominalised sentence from a central bank communiqué requires three or four verbal sentences to express the same content when unpacked, illustrating the compression achieved through nominalisation.
Unit 16
Digital Humanities
Exercise 11. take · 2. raises · 3. thorough · 4. suggests · 5. scant
Exercise 21. deeply → concerned / embedded / rooted · 2. utterly → exhausted / devastated / ridiculous · 3. bitterly → disappointed / cold / opposed · 4. highly → unlikely / regarded / skilled · 5. widely → regarded / available / acknowledged
Reading1. Semantic prosody is the tendency of "cause" to collocate with negative outcomes (damage, problems, death). It is discovered through corpus analysis — examining thousands of concordance lines reveals a pattern invisible to introspection. · 2. Traditional instruction focuses only on denotation (meaning), while corpus-informed instruction adds collocation (which words co-occur), frequency (how common a word is), and semantic prosody (evaluative colouring) — all essential for natural, pragmatically appropriate production.
Unit 17
Space Exploration
Exercise 11. Had · 2. Were · 3. Supposing · 4. might well · 5. not inconceivable
Exercise 21. Had · 2. Were · 3. is not inconceivable · 4. a viable atmosphere would develop · 5. Had
Reading1. That the trajectory of space exploration has been shaped as much by politics, economics, and accident as by technology — factors revealed when we consider the alternative paths that were not taken. · 2. If colonisation succeeds → it is a philosophical rupture (single-planet species no more) → if the colony becomes self-sustaining → questions of governance and sovereignty arise → given enough time, cultural, linguistic, and possibly biological divergence from Earth.
Unit 18
Social Justice
Exercise 11. People with disabilities need better access to public buildings. (Person-first language centres the person, not the condition.) · 2. Humanity has always sought to explore the unknown. (Gender-neutral alternative avoids the male default.) · 3. Many countries in the Global South lack adequate infrastructure. (Avoids the hierarchical and outdated term "third-world.") · 4. A nurse must always put their patients first. (Uses singular "they" to avoid gendered assumptions about the profession.) · 5. Homelessness is a growing concern in cities. / People experiencing homelessness face increasing challenges. (Person-first; avoids defining people by their circumstances.)
Exercise 21. undocumented migrants · 2. Older adults · 3. "they" · 4. developing · 5. identity-first language ("autistic person")
Reading1. Person-first language separates the person from the condition, while identity-first language (preferred by some Deaf and autistic communities) treats the condition as integral to identity. Neither is universally correct; the inclusive approach respects community preferences. · 2. Critics argue inclusive terminology can become euphemistic, obscuring severity and substituting for real change. The passage advises navigating with both sensitivity (attentive to naming power) and critical awareness (alert to the risk of language replacing action).
Unit 19
Artificial General Intelligence
Exercise 11. Claim (with qualifier "probably") · 2. Evidence · 3. Rebuttal · 4. Warrant · 5. Qualifier
Exercise 21. AI systems have already demonstrated capabilities beyond their designers' predictions, and the alignment problem — ensuring AI goals match human values — remains unsolved. · 2. If a sufficiently powerful system pursues goals misaligned with human survival, and we lack the ability to correct it, the consequences could be catastrophic and irreversible. · 3. This risk is not certain but constitutes a non-trivial probability that warrants serious precautionary action. · 4. Sceptics counter that current AI systems are narrow tools, not autonomous agents, and that the leap from language models to superintelligence may involve challenges we cannot yet foresee — possibly making AGI far more distant than alarmists suggest. · 5. While current systems are indeed narrow, the rate of capability improvement and the difficulty of predicting emergent behaviours at scale make complacency itself a risk.
Reading1. Claim: AGI without safety poses existential risk. Evidence: emergent capabilities, alignment difficulty, historical precedent. Warrant: precautionary — even low probability of civilisational extinction justifies action. Qualifier: "non-trivial" probability (5-50%). Rebuttal: current architectures may be fundamentally incapable of AGI. · 2. That the rebuttal contains an implicit gamble: if the sceptics are wrong about current architectures being incapable of AGI, the consequences are irreversible — making precaution the rational choice even in the face of uncertainty.
Unit 20
The Nature of Consciousness
Exercise 11. Never have scientists fully explained consciousness. · 2. The production of consciousness by the brain remains a phenomenon whose underlying mechanism has yet to be satisfactorily elucidated. · 3. Had Descartes possessed knowledge of modern neuroscience, he might well never have proposed dualism. · 4. It is not entirely clear that physicalism provides a fully adequate framework for understanding consciousness. · 5. Consciousness is an iceberg: what we are aware of is merely the visible tip, while the vast unconscious substrate lies submerged beneath the surface. Yet the metaphor has limits — unlike an iceberg, the unconscious is not simply a larger version of the conscious but may operate by entirely different principles.
Exercise 21. Stylistic inversion + tricolon · 2. Nominalisation + cause/effect · 3. Scientific hedging + data interpretation · 4. Counterfactual reasoning · 5. Performative verb + pragmatic inference (ironic certainty)
Reading1. The easy problems concern how the brain processes information, integrates data, and controls behaviour — tractable through neuroscience. The hard problem asks why physical processing is accompanied by subjective experience at all — a question that appears to resist purely physical explanation. · 2. The passage uses a counterfactual ("were consciousness to prove non-computable") to argue that the entire AGI project would need to be reconceived — linking the philosophical question of consciousness directly to the practical feasibility of artificial intelligence.