Narrator: Listen to part of a lecture in an environmental science class. Professor: Today we're going to talk about a fascinating phenomenon called 'urban heat islands.' This occurs when cities are significantly warmer than surrounding rural areas. The main cause is the replacement of natural surfaces with asphalt and concrete, which absorb and retain heat. Additionally, buildings and vehicles release waste heat, and the lack of vegetation reduces shade and evapotranspiration—the process where plants release water vapor, which cools the air. Now, one study in Phoenix, Arizona, found that nighttime temperatures in the city could be up to 10 degrees Celsius higher than in the desert nearby. This warming can lead to increased energy demand for air conditioning, which in turn burns more fossil fuels, creating a feedback loop. However, there are solutions, such as planting more trees, using reflective roofing materials, and creating green spaces. These strategies not only cool the city but also improve air quality and reduce runoff. So, as urban areas continue to expand, understanding and mitigating this effect becomes crucial.
❓ Question What is the main cause of the urban heat island effect, according to the lecture?
A. A. Increased use of air conditioning in cities.
B. B. Replacement of natural surfaces with heat-absorbing materials.
C. C. Release of heat from industrial processes.
D. D. Lack of rainfall in urban areas.
✅ Correct Answer
B. Replacement of natural surfaces with heat-absorbing materials.
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
