Narrator: Listen to part of a lecture in an environmental science class. Professor: Today we're going to talk about urban heat islands. You know that cities tend to be warmer than surrounding rural areas, sometimes by several degrees. Why is that? Well, one major factor is the materials we use to build. Concrete and asphalt absorb and retain heat during the day and release it slowly at night. Another factor is the lack of vegetation. Trees and green spaces provide shade and release moisture through transpiration, which cools the air. In cities, we replace those natural surfaces with roofs and roads. But here's an interesting solution: green roofs. These are rooftops covered with plants and soil. Research shows that green roofs can significantly reduce the surface temperature of a building, and they also help with stormwater management by absorbing rainwater. However, they're not a one-size-fits-all solution. Their effectiveness depends on climate, the types of plants used, and the building's structure. Older buildings may not support the extra weight. So, while green roofs are promising, we need to consider multiple factors before implementing them on a large scale.
❓ 문제 What is the professor's main point about green roofs?
A. They are the most effective solution to urban heat islands.
B. They are a promising solution but have limitations.
C. They are too expensive for most cities to adopt.
D. They work better in cold climates than in warm ones.
✅ 정답
They are a promising solution but have limitations.
TOEFL Listening Tips
Skim the questions first to predict the content
Watch for signal words in lectures and conversations (however, actually, in fact)
For main idea questions, focus on the beginning; for detail questions, focus on examples and data
For attitude questions, pay attention to the speaker's tone and word choice
Take notes on keywords; don't try to write down every word