정답 해설

[PASSAGE] Professor: Good morning, Sarah. Thanks for coming in. Your essay on historical volcanic eruptions and their climate impacts was quite insightful. However, I wanted to discuss a particular aspect you touched upon: the long-term vs. short-term effects. Student: So, the type and duration of volcanic activity are crucial. Professor: That would be an excellent re-framing. And perhaps consider how these geological volcanic CO2 emissions differ from anthropogenic CO2 emissions in terms of their release rate and magnitude. The professor initiates a conversation to discuss the long-term versus short-term effects of volcanic eruptions, which the student later refines to include the type and duration of volcanic activity. [WHY CORRECT] Option 3 is correct because the entire conversation centers on the distinction between the immediate cooling effects (short-term, aerosols) and the sustained warming effects (long-term, greenhouse gases) of different volcanic eruption types. The professor explicitly states the purpose is to discuss "the long-term vs. short-term effects," and the student's final proposed re-framing emphasizes "short-term stratospheric aerosol cooling versus long-term tropospheric greenhouse gas warming." [TRAPS] Option 1 is wrong because while the conversation starts from the student's essay, reviewing the essay itself is not the main purpose; it's a departure point for a deeper discussion. Option 2 is wrong because while long-term global warming mechanisms (greenhouse gases) are discussed, it's always in contrast to immediate cooling, making it only one half of the main topic. Option 4 is wrong because while halogen release and ozone depletion are mentioned as a "layer of complexity," it's a minor detail introduced at the end, not the central theme of the entire discussion. [TIP] For main idea questions, listen to the speaker's stated purpose at the beginning of the conversation and note any concluding summaries or re-framings of the discussion. These often explicitly state the core topic.

오답이 틀린 이유

• Option A (“To review the student's essay on the immediate cooling effects of volcanic erupt”) confuses two separate points from the text.
• Option B (“To delve into the geological mechanisms behind long-term global warming caused b”) swaps the cause and effect described in the passage.
• Option D (“To discuss the role of halogens released during volcanic eruptions on ozone depl”) attaches the right fact to the wrong subject.

문맥 속 핵심 표현

The language describing Volcanic Activity rewards close reading: notice contrast markers, hedging, and emphasis, since TOEFL detail items hinge on nuance rather than matching keywords.

학습 포인트

Match the answer word-for-meaning against the passage rather than the gist.