Narrator: Listen to part of a lecture in an environmental science class. Professor: Today we're going to talk about urban heat islands. As you know, cities tend to be warmer than surrounding rural areas, sometimes by several degrees. This is mainly because of the materials we use, like concrete and asphalt, which absorb and re-radiate heat. But there's a less obvious factor: the lack of vegetation. Trees and plants cool the air through a process called evapotranspiration, where water evaporates from leaves, taking heat with it. In rural areas, this natural cooling is abundant, but in cities, we've replaced green spaces with buildings and parking lots. Now, one solution is green roofs — covering rooftops with vegetation. Studies show that a green roof can reduce the surface temperature of a building by up to 40 degrees Fahrenheit in summer, and also lower the surrounding air temperature. Additionally, green roofs absorb rainwater, which reduces runoff and the burden on storm drainage systems. So, while they require initial investment, the long-term benefits for energy savings and urban climate are significant. Any questions?
❓ 문제 What is the main reason cities are warmer than rural areas, according to the professor?
A. A. The lack of vegetation, which reduces natural cooling through evapotranspiration.
B. B. The high density of buildings that block wind flow.
C. C. The use of materials that emit more heat than natural ground.
D. D. The increased energy use from air conditioning in summer.
✅ 정답
A. The lack of vegetation, which reduces natural cooling through evapotranspiration.
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
