テーマ: 有機食品の健康・環境面でのメリットをめぐる専門家間の論争を参考にしたオリジナル読解問題です。

■ 本文(オリジナル)

Organic food is often marketed as inherently healthier and more environmentally friendly than conventionally grown produce, but the scientific evidence is far more mixed than most consumers assume. Several large studies have found little measurable difference in nutritional content between organic and conventional fruits and vegetables, even though organic produce typically contains lower pesticide residues. Meanwhile, organic farming tends to produce lower yields per acre, meaning that a complete shift to organic methods would likely require converting additional land to agriculture, with potentially serious consequences for wild habitats. Supporters counter that these calculations ignore the long-term damage caused by synthetic fertilizers, including soil degradation and water pollution. They argue that the true cost of conventional farming is simply hidden rather than absent. Given these competing considerations, deciding whether organic farming deserves greater public support requires weighing immediate costs against long-term environmental risks, rather than assuming that either approach is obviously superior.

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■ 設問1: 和訳問題

次の下線部を日本語に訳しなさい。

“Given these competing considerations, deciding whether organic farming deserves greater public support requires weighing immediate costs against long-term environmental risks.”

【解答】
これらの相反する考慮事項を踏まえると、有機農業がより多くの公的支援に値するかどうかを判断するには、目先のコストと長期的な環境リスクを比較検討することが必要である。

【解説】
文構造: [分詞構文: Given(過去分詞) these competing considerations], [S: deciding whether organic farming deserves greater public support(動名詞句=主語)] [V: requires(動詞)] [O: weighing(動名詞) immediate costs against long-term environmental risks]
品詞: Given(過去分詞から始まる分詞構文「〜を考慮すると」という慣用表現)、deciding(動名詞、文の主語)、whether(接続詞、「〜かどうか」という名詞節を導く)、weighing A against B「AとBを比較検討する」
ポイント: Given + 名詞は「〜を踏まえると」という意味の分詞構文由来の慣用表現(前置詞的に使われる)。文の主語が動名詞句(deciding whether…)という長い名詞相当語句になっている点にも注目。

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■ 設問2: 並べ替え問題

かっこ内の語句を正しく並べ替え、意味の通る英文を完成させなさい。

Organic farming ( tends to / produce / lower yields per acre / meaning that / a complete shift to organic methods / would likely require / converting / additional land / to agriculture ).

【解答】
Organic farming tends to produce lower yields per acre, meaning that a complete shift to organic methods would likely require converting additional land to agriculture.
有機農業は1エーカーあたりの収量が低くなる傾向があり、そのことは、有機農法へと完全に転換すれば、追加の土地を農地に転換することがおそらく必要になるということを意味している。

【解説】
文構造: [S: Organic farming(名詞句)] [V: tends to produce(動詞句)] [O: lower yields per acre(名詞句)], [分詞構文: meaning(現在分詞) that a complete shift to organic methods would likely require converting additional land to agriculture(名詞節)]
品詞: tends to produce(tend to do「〜する傾向がある」)、meaning that…(分詞構文、「つまり〜ということだ」という結果・言い換えを表す慣用的な用法)、would require(仮定法的なwould、一般論としての推量)、converting(動名詞、requireの目的語)
ポイント: meaning that… は文末に置かれ、前の内容を「つまり〜という意味だ」と言い換える分詞構文の定番パターン。require doing「〜することを必要とする」も確認しておく。

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■ 設問3: 語句変形問題(3問)

次の各文の( )内の語を、文脈に合う適切な形に変えなさい。

1. Several large studies have found little measurable difference in nutritional content, even though organic produce typically contains (low) pesticide residues.
2. Supporters counter that these calculations ignore the long-term damage (cause) by synthetic fertilizers.
3. They argue that the true cost of conventional farming is simply hidden rather than (absent, 反意語の形容詞に).

【解答と解説】

1. 正解: lower
   文構造: [S: organic produce(名詞句)] [V: contains(動詞)] [O: lower(比較級の形容詞) pesticide residues(名詞句)]
   品詞: lower(形容詞lowの比較級、pesticide residuesを修飾)
   解説: 文全体がconventional(慣行栽培)と比較する文脈なので、原級lowではなく比較級lowerが正しい。「(慣行栽培より)低い残留農薬」という相対的な比較を表す。
2. 正解: caused
   文構造: [O: the long-term damage(名詞句)] ← [過去分詞句: caused(過去分詞) by synthetic fertilizers(前置詞句)]
   品詞: caused(過去分詞、damageを後置修飾)
   解説: damageとcauseは受動関係(損害が引き起こされる)なので過去分詞。「合成肥料によって引き起こされた長期的な損害」という意味になる。
3. 正解: absent(反意語ではなく、文脈上そのままabsentが正解)
   文構造: [C: hidden(過去分詞・形容詞的用法)] rather than [C: absent(形容詞)]
   品詞: absent(形容詞「存在しない」)、hidden(形容詞的に使われる過去分詞「隠された」)
   解説: rather than A but B「BであってAではない」に近いA/B比較の構造で、hiddenとabsentという対照的な形容詞が並置されている。「本当のコストは存在しないのではなく、単に隠されているだけだ」という文意になるようabsentのままが正しい(語形自体は変化なし、対比構造の理解を問う設問)。

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■ 設問4: 内容一致・言い換え・解釈問題(3問)

本文の内容に関する次の各問いに対して、最も適切なものを1つずつ選びなさい。

1. According to the passage, what have several large studies found regarding organic and conventional produce?
   (A) Organic produce is significantly more nutritious than conventional produce.
   (B) There is little measurable difference in nutritional content between the two, although organic has lower pesticide residues.
   (C) Conventional produce contains no pesticide residues at all.
   (D) Organic produce always has much higher yields than conventional produce.
2. Which of the following best paraphrases “the true cost of conventional farming is simply hidden rather than absent”?
   (A) Conventional farming has no hidden costs at all.
   (B) The costs of conventional farming still exist, even though they are not immediately visible.
   (C) Conventional farming is completely free of any negative consequences.
   (D) Organic farming has more hidden costs than conventional farming.
3. What concern do critics raise about a complete shift to organic farming, according to the passage?
   (A) It would require converting additional land to agriculture because of lower yields per acre.
   (B) It would eliminate all pesticide use immediately.
   (C) It would have no effect on wild habitats.
   (D) It would make food nutritionally superior overnight.

【解答と解説】

1. 正解: (B)
   本文該当箇所: “Several large studies have found little measurable difference in nutritional content between organic and conventional fruits and vegetables, even though organic produce typically contains lower pesticide residues.”
   解説: 栄養面での差はほとんどないが、農薬残留量は有機の方が低いという内容と一致。(A)(C)(D)は本文の内容と矛盾。
2. 正解: (B)
   本文該当箇所: “the true cost of conventional farming is simply hidden rather than absent”
   解説: hidden(隠れている)rather than absent(存在しない、ではなく)という対比から、「コストは見えないだけで実際には存在する」という意味になる。(A)(C)は真逆の内容。
3. 正解: (A)
   本文該当箇所: “organic farming tends to produce lower yields per acre, meaning that a complete shift to organic methods would likely require converting additional land to agriculture, with potentially serious consequences for wild habitats”
   解説: 収量の低さゆえに追加の土地が必要になり、野生生物の生息地への影響が懸念されるという内容と一致。(B)(C)(D)は本文に記述なし、または矛盾。