Listen to part of a lecture in an environmental science class. The professor is discussing the concept of urban heat islands.
"Now, urban areas tend to be warmer than surrounding rural areas, a phenomenon we call the urban heat island effect. This happens mainly because materials like concrete and asphalt absorb and re-radiate solar heat more efficiently than natural vegetation. Additionally, waste heat from vehicles, air conditioners, and industrial processes adds to the temperature. Interestingly, the intensity of this effect varies with time of day. In many cities, the temperature difference between urban and rural areas is largest at night, because urban surfaces slowly release the heat they absorbed during the day, while rural areas cool down more quickly. The effect also depends on weather conditions. Clear, calm nights enhance the heat island, while windy or cloudy conditions reduce it. To mitigate this, cities use strategies like planting trees, installing green roofs, and using reflective pavement materials. These measures not only lower temperatures but also reduce energy consumption for cooling."
Now the professor mentions strategies to mitigate the effect. Listen to the following question.
❓ 题目 What does the professor say about the timing of the urban heat island effect?
A. A. It is strongest during the middle of the day when the sun is hottest.
B. B. It is most noticeable at night because urban surfaces release heat slowly.
C. C. It is equally strong at all times of day and night.
D. D. It occurs only in the early morning before sunrise.
✅ 正确答案
B. It is most noticeable at night because urban surfaces release heat slowly.