【改訂版】TOEFL Reading：要約問題解法（の一部）

2022.10.16

Reading対策

以下、過去に書いた記事をまとめて内容を改訂したものです。

TOEFL iBT Reading問題の“ボスキャラ”とでもいうべき問題が「要約問題」（Prose Summary Question）。Readingセクションで様々な敵（問題）を倒した後、ステージの最後に現れる強敵。このボスキャラを攻略しない限りReadingは高得点になりません。しかしボスキャラにはだいたい弱点があるように Readingの要約問題にも正しい攻略法があります。
今回の記事では、要約問題の攻略法（解法）の一部を紹介します。

以下、トフレのReadingコースで教材として採用している問題集の問題（オンライン授業では扱わないアサインメントの問題）の抜粋です。

パッセージのタイトルは“Water Loss”。ですがここではパッセージは表示しません。

設問と選択肢だけを読んで、解答して下さい。目標解答時間は2分。

是非、時間を計って2分以内に解けたか確認して下さい（要約問題は本試験においても2分以内を目安に解くべき問題なので）。
「パッセージが無いのに解答できるわけがないじゃないか！」と思われて当然ですが、「設問と選択肢のみ」でどの選択肢が正解になりやすいと思われるか判断して下さい。

皆さんなりに

・正解の可能性が高い選択肢はどれか？

・その根拠は何か？

をよく考えてください。要約問題は選択肢に対する視点が大切であり、まずは自分なりの視点を確認しましょう。

An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.

The human body needs a constant supply of water for metabolism.

・

A) Water lost through evaporation from respiratory and body surfaces must be replaced.

B) Water is an important product of the oxidation of carbohydrates.

C) Given water to drink, humans can tolerate high temperatures by using the cooling method of sweating.

D) A scientist remained in a 260-degree room for 45 minutes, which was long enough to cook a steak.

E) Unless water is replaced by drinking, continuous sweating will eventually lead to collapse and death.

F) No human has ever survived more than two days in a desert without water.

では、解説を始めます。要約問題解法のカギの1つ、それはintroductory sentenceです。

TOEFL iBT Reading問題を解いたことがありながら「introductory sentence ？何それ？」という方は、いらっしゃらないはず。要約問題は

An introductory sentence for a brief summary of the passage is provided below.

から始まります。この問題なら

The human body needs a constant supply of water for metabolism.

「人体は、代謝のために安定した水の供給を必要とする」

がintroductory sentence。パッセージの内容を漠然とまとめた要約の導入文が、実は解答において大切なのです。要約問題を解く際、introductory sentenceを読まずに解答していたら非常にモッタイナイこと。

要約問題では introductory sentenceの主語や抽象的な表現など意味的に重要そうな表現に注目しましょう。

なぜなら

introductory sentenceの主語や抽象的な表現を具体化した選択肢、それらの表現と結びつきの強い選択肢が正解になりやすい

から。言い換えれば

introductory sentenceと関連性の低い選択肢は、不正解の可能性が高い

6つの選択肢の中で、introductory sentenceとの結びつきが低いと思われるものはどれでしょうか？

要約問題の解法ポイントをもう1つ紹介します。毎回同じ表現で出題される要約問題の設問は

Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage.

「パッセージに書かれていないものやminor ideasを述べているものは不正解になる」

と言っています。

パッセージに記述がないものをパッセージの要約に含めるべきではないのは当然として、ここでの“minor ideas”とは何を意味するのか？それが明確に分かっていないと、どのような選択肢が不正解になるのか判断できません。ここでのminor ideasが意味するのは、具体例です。

TOEFL iBT Readingのパッセージでは、段落最初のあたりでその段落のmain ideaを抽象的に表し、その後、そのmain ideaをサポートする具体例が続く展開が多いことはご存知かと思います。

具体例は main ideaをサポートするためのものであり、要約にふさわしいmain ideas（= important ideas）ではありません。

よって要約問題の選択肢において、具体例の内容になっている選択肢は不正解になります。

「具体例はダメ！」なので「選択肢の表現が具体的で細かいものは正解になりにくい」と言えます。

まとめます。

・introductory sentenceとの関連性の低いものは不正解の可能性が高い

・具体的で細かい表現が使われているものは不正解の可能性が高い

この2つの視点に基づいて、不正解になりやすそうな選択肢を消去して残った3つは何になりますか？もう答えは分かりましたね。

以上から、不正解になりやすいと判断できる選択肢は、

B）Water is an important product of the oxidation of carbohydrates.

理由：introductory sentenceとの関連性が低い。「人体」や「安定した水の供給」に触れていない。oxidation or carbohydrates「炭水化物の酸化」は具体的で細かい表現。

D) A scientist remained in a 260-degree room for 45 minutes, which was long enough to cook a steak.

理由：introductory sentenceの重要なキーワード「水」に触れていない。明らかに具体的で細かい表現（例：260-degree room、45 minutes、cook a steak）。本文に合っている内容だとしても具体例のはず。

F) No human has ever survived more than two days in a desert without water.

理由：two days in a desertという具体的で細かい表現。

そして、これらを消去した残りのA、C、Eが正解になる可能性の高い選択肢です。

そのどれもintroductory sentenceでの主語や抽象的表現である「人体」「安定した水の供給」との結びつきが強く、比較的抽象的な表現が使われています。

A）Water lost through evaporation from respiratory and body surfaces must be replaced.

C）Given water to drink, humans can tolerate high temperatures by using the cooling method of sweating.

E）Unless water is replaced by drinking, continuous sweating will eventually lead to collapse and death.

実際にテキストの問題の正解は、A、C、Eです。

ただ、ここでお話ししているのは、正解・不正解の「可能性の高い」選択肢であり、傾向的に正解になりそうな選択肢であっても本文に書かれていないものであれば当然不正解になります。しかしこれらの傾向によって、選択肢を1つ、2つと消去できる要約問題も多いため、今後問題を解く際は、上記の視点に基づいて選択肢を判断しましょう（「具体的で細かい表現」が入っていれば、正解になりにくいとは言えますが、正解にならないということではないので注意してください）。

では今度はETS作成の問題を解いていただきます。The TOEFL iBT Test Prep Planner (pp. 44-47）で公開されているReadingの要約問題を「設問と選択肢だけ」から解答して下さい。パッセージのタイトルは Meteorite Impact and Dinosaur Extinction です。

Q. An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.

A meteorite impact on Earth may have contributed to the mass extinction of species at the end of the Cretaceous period.

・

Answer choices

A）Scientists had believed for centuries that meteorite activity influenced evolution on Earth.

B）The site of the large meteorite impact at the end of the Cretaceous period was identified in 1990.

C）There have also been large meteorite impacts on the surface of the Moon, leaving craters like Tycho.

D）An iridium-enriched sediment layer and a large impact crater in the Yucatán provide evidence that a large meteorite struck Earth about 65 million years ago.

E）Large meteorite impacts, such as one at the end of the Cretaceous period, can seriously affect climate, ecological niches, plants, and animals.

F）Meteorite impacts can be advantageous for some species, which thrive, and disastrous for other species, which become extinct.

どの選択肢が正解の可能性が高いと思いますか？

この問題のポイントはintroductory sentenceとのつながり。

是非、以下のパッセージを読んだ上で正解を確認ください。（正解はこのページの下に表示しています）

Meteorite Impact and Dinosaur Extinction

There is increasing evidence that the impacts of meteorites have had important effects on Earth, particularly in the field of biological evolution. Such impacts continue to pose a natural hazard to life on Earth. Twice in the twentieth century, large meteorite objects are known to have collided with Earth.

If an impact is large enough, it can disturb the environment of the entire Earth and cause an ecological catastrophe. The best-documented such impact took place 65 million years ago at the end of the Cretaceous period of geological history. This break in Earth’s history is marked by a mass extinction, when as many as half the species on the planet became extinct. While there are a dozen or more mass extinctions in the geological record, the Cretaceous mass extinction has always intrigued paleontologists because it marks the end of the age of the dinosaurs. For tens of millions of years, those great creatures had flourished. Then, suddenly, they disappeared.

The body that impacted Earth at the end of the Cretaceous period was a meteorite with a mass of more than a trillion tons and a diameter of at least 10 kilometers. Scientists first identified this impact in 1980 from the worldwide layer of sediment deposited from the dust cloud that enveloped the planet after the impact. This sediment layer is enriched in the rare metal iridium and other elements that are relatively abundant in a meteorite but very rare in the crust of Earth. Even diluted by the terrestrial material excavated from the crater, this component of meteorites is easily identified. By 1990 geologists had located the impact site itself in the Yucatán region of Mexico. The crater, now deeply buried in sediment, was originally about 200 kilometers in diameter.

This impact released an enormous amount of energy, excavating a crater about twice as large as the lunar crater Tycho. The explosion lifted about 100 trillion tons of dust into the atmosphere, as can be determined by measuring the thickness of the sediment layer formed when this dust settled to the surface. Such a quantity of material would have blocked the sunlight completely from reaching the surface, plunging Earth into a period of cold and darkness that lasted at least several months. The explosion is also calculated to have produced vast quantities of nitric acid and melted rock that sprayed out over much of Earth, starting widespread fires that must have consumed most terrestrial forests and grassland. Presumably, those environmental disasters could have been responsible for the mass extinction, including the death of the dinosaurs.

Several other mass extinctions in the geological record have been tentatively identified with large impacts, but none is so dramatic as the Cretaceous event. But even without such specific documentation, it is clear that impacts of this size do occur and that their results can be catastrophic. What is a catastrophe for one group of living things, however, may create opportunities for another group. Following each mass extinction, there is a sudden evolutionary burst as new species develop to fill the ecological niches opened by the event.

Impacts by meteorites represent one mechanism that could cause global catastrophes and seriously influence the evolution of life all over the planet. According to some estimates, the majority of all extinctions of species may be due to such impacts. Such a perspective fundamentally changes our view of biological evolution. The standard criterion for the survival of a species is its success in competing with other species and adapting to slowly changing environments. Yet an equally important criterion is the ability of a species to survive random global ecological catastrophes due to impacts.

Earth is a target in a cosmic shooting gallery, subject to random violent events that were unsuspected a few decades ago. In 1991 the United States Congress asked NASA to investigate the hazard posed today by large impacts on Earth. The group conducting the study concluded from a detailed analysis that impacts from meteorites can indeed be hazardous. Although there is always some risk that a large impact could occur, careful study shows that this risk is quite small.