การฟัง TOEFL

🎧 บทถอดเสียง

Narrator: Listen to part of a lecture in an environmental science class. Professor: Today we're going to discuss the concept of 'green roofs'—rooftops partially or completely covered with vegetation. While they might seem like a modern trend, green roofs have ancient roots, like the famous Hanging Gardens of Babylon. However, their modern resurgence is driven by practical benefits. First, they reduce stormwater runoff by absorbing rainwater, which lessens the burden on urban drainage systems. Second, they provide insulation, cutting energy costs for heating and cooling. Third, they mitigate the 'urban heat island' effect, where cities are warmer than surrounding rural areas due to concrete and asphalt absorbing heat. But there are challenges: installation costs are high, and roofs must be structurally reinforced to support the extra weight. Maintenance is also ongoing, requiring irrigation and weeding. Despite these drawbacks, many cities now offer incentives, such as tax breaks, to encourage their adoption. So, while not a one-size-fits-all solution, green roofs represent a promising strategy for sustainable urban development.