Narrator: Listen to part of a lecture in an environmental science class. Professor: Today we're going to talk about the concept of 'urban heat islands.' This occurs when cities are significantly warmer than surrounding rural areas. Why? Well, one major reason is the replacement of natural vegetation with asphalt, concrete, and buildings. These materials absorb and re-radiate solar energy more than soil and plants do. Another factor is waste heat from vehicles, air conditioners, and industrial processes. Interestingly, the temperature difference is often most pronounced at night, because the urban materials slowly release the heat they absorbed during the day, whereas rural areas cool off more quickly. This effect can have serious consequences, such as increased energy demand for cooling, higher emissions of pollutants, and even heat-related health issues. Some solutions include planting more trees, creating green roofs, and using reflective materials on pavements and buildings. These strategies not only reduce local temperatures but also improve air quality and stormwater management. So, mitigating the urban heat island effect is a key part of sustainable city planning.
❓ 题目 According to the professor, why is the urban heat island effect often most noticeable at night?
A. A. Because rural areas absorb more heat during the day.
B. B. Because urban materials release stored heat slowly after sunset.
C. C. Because waste heat from vehicles increases only at night.
D. D. Because reflective materials are less effective in the dark.
✅ 正确答案
B. Because urban materials release stored heat slowly after sunset.