การฟัง TOEFL

🎧 บทถอดเสียง

Narrator: Listen to part of a lecture in an environmental science class. Professor: Today we're talking about urban heat islands, a phenomenon where cities are significantly warmer than surrounding rural areas. One major cause is the replacement of natural surfaces, like soil and vegetation, with materials such as concrete and asphalt, which absorb and retain heat. Another factor is waste heat from buildings and vehicles. But there's a lesser-known contributor: the loss of trees. Trees provide shade and release moisture through transpiration, which cools the air. When we remove trees to build roads and parking lots, we eliminate this natural cooling effect. Interestingly, studies show that even small green spaces, like community gardens, can reduce local temperatures by several degrees. So, what can cities do? One solution is green roofs—planting vegetation on rooftops, which not only insulates buildings but also lowers ambient temperatures. Another is using reflective materials on pavements. However, these measures require investment and policy changes. The key is to think holistically about urban design. Now, let's consider a specific case...