Listen to part of a lecture in an environmental science class. Professor: Today we're discussing the concept of 'green roofs'—rooftops covered with vegetation. Now, 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, their modern revival is driven by urban heat islands, stormwater management, and air quality. One key benefit is that plants absorb rainwater, reducing runoff that can overwhelm sewer systems. Also, they lower building energy costs by providing natural insulation. But there are challenges: the upfront cost is high, and the roof must be structurally sound to support the weight of soil and plants. Maintenance can be intensive, requiring irrigation in dry periods. Despite these drawbacks, many cities offer tax incentives to encourage installation. So, while the initial investment is significant, the long-term environmental and economic benefits often outweigh the costs. Now, who can think of a potential downside beyond cost?
❓ คำถาม What is one of the main environmental benefits of green roofs mentioned by the professor?
A. They provide extra living space for urban residents.
B. They reduce stormwater runoff and lower building energy costs.
C. They eliminate the need for any maintenance or irrigation.
D. They increase the urban heat island effect.
✅ คำตอบที่ถูกต้อง
They reduce stormwater runoff and lower building energy costs.
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