Listen to part of a lecture in an environmental science class. The professor is discussing the concept of urban heat islands.
Professor: Today we're going to talk about urban heat islands, a phenomenon where cities are significantly warmer than surrounding rural areas. This happens mainly because of the materials used in construction, like concrete and asphalt, which absorb and retain heat more than natural landscapes. Also, cities have less vegetation, which means less shade and less cooling through evapotranspiration. Additionally, waste heat from vehicles and air conditioning units adds to the problem. The temperature difference can be as much as 10 degrees Fahrenheit on a clear night. To mitigate this, some cities are implementing green roofs, planting trees, and using reflective materials on buildings and roads. These measures not only lower temperatures but also reduce energy consumption and improve air quality. While the cost of retrofitting existing structures can be high, the long-term benefits are significant.
❓ Pregunta According to the professor, what is a primary cause of urban heat islands?
A. A large number of vehicles and factories
B. The use of heat-absorbing materials and lack of vegetation
C. The absence of wind in city areas
D. The high population density in urban centers
✅ Respuesta correcta
The use of heat-absorbing materials and lack of vegetation
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
