Narrator: Listen to part of a lecture in an environmental science class.
Professor: So today we're talking about urban heat islands. Now, cities tend to be warmer than surrounding rural areas, and this is due to several factors. One major factor is the replacement of natural surfaces with concrete and asphalt, which absorb and retain heat during the day and release it slowly at night. Another factor is the lack of vegetation, which normally provides shade and cools the air through evapotranspiration. But there's an interesting solution that some cities are adopting: green roofs. A green roof is a roof that is partially or completely covered with vegetation and a growing medium, planted over a waterproof membrane. These roofs can reduce the surface temperature of the building, lower energy costs for cooling, and even reduce stormwater runoff. However, they also have some challenges, such as higher initial installation costs and the need for structural reinforcement to support the weight. So, while green roofs are not a one-size-fits-all solution, they represent a promising strategy to mitigate the effects of urban heat islands.
❓ 题目 What does the professor say about green roofs?
A. A) They are the most effective solution for all cities.
B. B) They replace natural surfaces with concrete and asphalt.
C. C) They can lower building temperatures and reduce runoff but have higher upfront costs.
D. D) They primarily work by providing shade through tall trees.
✅ 正确答案
C) They can lower building temperatures and reduce runoff but have higher upfront costs.