Чтение и письмо: обзор вариантов (модальность и условие)
Слова урока · 4
- option appraisal /ˈɒpʃn əˌpreɪzl/оценка вариантов
- criterion /kraɪˈtɪəriən/ criteriaкритерий
- trade-off /ˈtreɪd ɒf/компромисс, размен
- do-nothing option /ˌduː ˈnʌθɪŋ ˌɒpʃn/вариант «ничего не делать»
Фразы урока · 2
- An option appraisal compares like with like — four criteria: cost, effectiveness, reversibility, time.Оценка вариантов сравнивает сопоставимое; четыре критерия: стоимость, эффективность, обратимость, время.
- The trade-off is cost against certainty; always cost the do-nothing option.Размен — стоимость против определённости; всегда оценивайте вариант «ничего не делать».
Текст: «Оценка вариантов: защита Ривер-стрит от наводнений»
1. What we know. River Street has flooded twice in ten years (2015, 2019). Forty houses were affected each time; the 2019 repair bill was £1.2m, of which insurers paid £0.9m. In March, the two main insurers wrote to say that they will not renew cover for the street after 2027 «in the absence of a permanent defence».
2. What we assume. The central climate projection gives a 10 % rise in winter rainfall by 2040; on that basis the hydrologist puts a further flood before 2035 at about 60 %. A wall is assumed to last 50 years. The cost of a wall is a single contractor's quote of £5m, ± 20 % pending a ground survey (due March). The upstream storage scheme is assumed not to be built before 2030; it is unfunded.
3. Options.
A. Wall (£5m, of which a grant may cover £2.5m — confirmed in principle, not in writing). Effective against all recorded floods. Permanent; not reversible. Risk: may shift some flooding downstream to the mill (hydrologist: 30 %, to be modelled by spring). Time to build: 18 months.
B. Temporary barriers (£0.4m, plus £30k a year). Effective in 2019-scale floods if deployed in time; volunteers required. Reversible. Do not satisfy the insurers' condition. Time: 3 months.
C. Wait for the upstream scheme (£0). Would remove the need for A or B if built. Unfunded; earliest 2030. Insurers withdraw in 2027; houses become uninsurable for at least three years.
D. Do nothing (£0). Expected cost of floods to 2040 at 60 % probability: roughly £1.5m to householders once cover is withdrawn, plus loss of value estimated at 30–50 % of the street's housing stock.
4. Trade-offs. A buys certainty at the highest price and is irreversible; B buys time cheaply but does not solve the insurance problem; C is free and may conceivably solve everything, but not in time; D is the most expensive option in expectation, borne by households rather than the council.
5. Sensitivity. The case for A is sensitive to two assumptions: the grant (without it, A costs the council £5m and the case weakens sharply) and the rainfall figure (at a 5 % rise, the probability of a flood before 2035 falls to about 45 %, and A still pays, but over 30 years rather than 20).
Задание
Напишите взвешенную рекомендацию (recommendation section, 300–340 слов) для совета по материалам оценки вариантов: карта неопределённости (what we know / assume / contest; a known unknown); вероятности откалиброванными словами (bound to; on the balance of probabilities; might well; may conceivably; remote); ключевое обстоятельство (if it were not for / but for the insurers' letter …; the case hinges on …); временные планы (in hindsight … would have; as things stand; may yet; by then); рекомендация с условиями, потолком, триггером, датой пересмотра и запасным вариантом (provided that; subject to; ceiling; I would revisit this if; review date; fall-back); прямой ответ с оговоркой (the short answer is …; one caveat; I can't rule out … but).
Образец ответа
Recommendation: River Street flood protection
What we know is narrow but firm: two floods in ten years, forty houses each time, a £1.2m bill in 2019, and an insurers' letter withdrawing cover after 2027 without a permanent defence. What we assume is wider: a 10 % rise in winter rainfall, a 50-year wall, a single quote of £5m ± 20 %, and no upstream scheme before 2030. What is contested is only the downstream effect on the mill. The date of the next flood is a known unknown.
On probabilities: the street is bound to flood again; on the balance of probabilities it does so before 2035 — the hydrologist puts it at 60 %, and at a 5 % rainfall rise still about 45 %. The upstream scheme may conceivably remove the need for any defence, but it is unfunded and cannot be in place before cover is withdrawn. The chance that the coming decade spares us is remote.
The case hinges on the insurers' letter. But for that letter, temporary barriers would be the sensible choice: cheap, reversible and proven at the 2019 scale. With it, barriers leave forty houses uninsurable from 2027, and the loss of value — 30–50 % — exceeds the cost of the wall many times over. In hindsight, a wall in 2019 would have paid for itself in that one winter; as things stand, the quote is higher and the grant is not yet in writing.
The short answer is: build the wall. On present evidence, I recommend option A, provided that the grant of £2.5m is confirmed in writing before contracts are signed, and subject to the ground survey due in March. The cost ceiling is £6m; above that, we walk away and revisit. I would also revisit this if the downstream model shows more than minor transfer to the mill, or if the upstream scheme is funded — it may yet be, and by then we would want the wall designed to complement it, not to duplicate it. Review date: March. Fall-back: buy barriers now (£0.4m) as a bridge and as insurance against the wall falling through.
One caveat: the cost rests on one quote. I can't rule out an overrun, but I would plan on £5m and let the survey, not a hope, set the final figure.
lightbulbРекомендация по оценке вариантов: карта (known / assumed / contested / known unknown) → вероятности словами и числами → the case hinges on; but for … → in hindsight / as things stand / may yet → the short answer is: X, provided that, subject to, ceiling, revisit if, review date, fall-back → one caveat.
Закрепите урок: упражнения со словами, фразами и грамматикой с проверкой и повторением.