Listen to part of a lecture in an environmental science class. Professor: Today we're going to discuss the concept of 'urban heat islands' and some surprising solutions. Urban areas, as you know, tend to be warmer than surrounding rural areas because concrete and asphalt absorb and re-radiate heat. But recent research suggests that painting rooftops white—what we call 'cool roofs'—can significantly reduce this effect. White surfaces reflect sunlight rather than absorbing it, so buildings stay cooler, requiring less air conditioning. This not only lowers energy bills but also cuts greenhouse gas emissions. However, there's a catch. A study from Purdue University found that in cooler climates, white roofs might increase heating costs during winter because they reflect away valuable solar warmth. So, the climate matters. In tropical regions, cool roofs are a no-brainer. But in temperate zones, we need to weigh the summer savings against winter losses. Some cities are now using a combination of green roofs—covered with vegetation—and cool roofs, depending on local conditions. The key is to adapt the solution to the specific environment. Now, can anyone think of why green roofs might be more beneficial in some cases?
❓ Question What does the professor say about the effectiveness of cool roofs?
A. They are always beneficial regardless of climate.
B. They are more effective in warm climates than in cold ones.
C. They work best in temperate zones because of winter heating.
D. They increase energy costs in all regions.
✅ Correct Answer
They are more effective in warm climates than in cold ones.
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