Listen to part of a lecture in an environmental science class. Professor: Today we're going to talk about urban heat islands. This phenomenon occurs when cities are significantly warmer than surrounding rural areas. One major cause is the replacement of natural surfaces, like soil and vegetation, with materials like concrete and asphalt, which absorb and retain heat. Also, buildings and roads trap heat during the day and release it slowly at night. But there are solutions. For instance, 'green roofs'—covering rooftops with plants—can reduce surface temperatures by up to 30 degrees Celsius. Another approach is increasing the albedo of surfaces, meaning making them more reflective, such as using white paint or reflective materials on roofs and pavements. Studies have shown that these strategies not only cool the air but also reduce energy consumption for air conditioning. However, implementing them requires city planning and public investment. So, while individual actions help, systemic changes are crucial for long-term relief. Now, let's consider the economic implications...
❓ Question According to the professor, what are two main causes of urban heat islands?
A. A. Lack of green spaces and high vehicle emissions
B. B. Absorption of heat by building materials and lack of vegetation
C. C. Excessive use of air conditioning and tall buildings
D. D. Increased albedo and reflective surfaces
✅ Correct Answer
B. Absorption of heat by building 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
