การฟัง TOEFL

🎧 บทถอดเสียง

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. This is due to several factors. First, concrete and asphalt absorb and retain heat during the day, and release it slowly at night. Second, buildings block wind, reducing natural cooling. Third, there's less vegetation, which means less shade and less evapotranspiration—the process where plants release water vapor, which cools the air. But there are solutions. One is to plant more trees and create green roofs—roofs covered with vegetation. These can lower surface temperatures significantly. Another is to use reflective materials on roofs and pavements, which bounce sunlight back instead of absorbing it. A study in a large city showed that increasing tree cover by 20% could reduce peak summer temperatures by up to 2 degrees Celsius. However, such measures require investment and policy changes. So, while the problem is serious, we have practical ways to mitigate it. Any questions?