Listen to part of a lecture in an environmental science class.
Today we're going to talk about urban heat islands, a phenomenon where cities are significantly warmer than surrounding rural areas. This happens because concrete, asphalt, and buildings absorb and re-emit heat from the sun more than natural landscapes do. Additionally, waste heat from vehicles, air conditioners, and industrial processes adds to the effect. But there are solutions. One effective strategy is increasing urban greenery—planting trees and creating parks. Trees provide shade and release moisture through transpiration, which cools the air. Another approach is using cool roofs, which are painted white or made with reflective materials to bounce sunlight back into the atmosphere. Studies show that cool roofs can reduce a building's cooling costs by up to 15 percent. However, implementing these solutions requires cooperation between city planners, architects, and residents. While individual actions, like planting a tree, help, systemic changes are necessary for meaningful impact. So, the challenge is not just technical but also social and political.
❓ 题目 What is the main purpose of the lecture?
A. To explain why urban heat islands occur and discuss potential solutions
B. To argue that cool roofs are more effective than planting trees
C. To describe the history of urban development in major cities
D. To encourage students to plant trees in their own neighborhoods
✅ 正确答案
To explain why urban heat islands occur and discuss potential solutions