Narrator: Listen to part of a lecture in an environmental science class. Professor: Today we're going to talk about the concept of 'green roofs'—rooftops covered with vegetation. Now, many of you might think this is just a modern trend, but green roofs have been around for centuries, especially in cold climates where they provided insulation. However, the modern push for green roofs in urban areas is driven by a different set of benefits. First, they reduce stormwater runoff. In cities with lots of impervious surfaces, heavy rain can overwhelm sewer systems. Green roofs absorb rainwater, slowing the release into drains. Second, they mitigate the urban heat island effect. The plants and soil absorb less heat than traditional dark roofing materials, and they also release moisture through evapotranspiration, which cools the air. Finally, green roofs extend the lifespan of the roofing membrane by protecting it from UV radiation and temperature extremes. So, while the initial cost is higher, the long-term savings in energy and maintenance can be significant. Any questions?
❓ Question According to the professor, what is one reason that modern green roofs are promoted in cities?
A. They provide insulation in cold climates, as they have for centuries.
B. They help manage stormwater by absorbing rainfall and reducing runoff.
C. They are cheaper to install than traditional roofing materials.
D. They completely eliminate the urban heat island effect.
✅ Correct Answer
They help manage stormwater by absorbing rainfall and reducing runoff.
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