Listen to part of a lecture in an environmental science class. Professor: Today we're going to discuss a surprising factor that affects urban temperatures: the color of roofs. You might know that dark surfaces absorb more heat from the sun, while light surfaces reflect it. This principle underlies the 'cool roof' movement, where buildings in hot climates have white or reflective coatings to reduce air conditioning needs. However, a recent study from a team at MIT suggests that in colder regions, cool roofs might actually increase heating costs. In these areas, dark roofs help absorb heat during winter, reducing the energy needed to warm buildings. The researchers simulated different roof colors in various climates and found that the optimal choice depends on a balance between summer cooling and winter heating. They also noted that cool roofs can lower city-wide temperatures, which helps mitigate the urban heat island effect. So, the decision isn't as simple as 'always use white roofs.' It requires a local analysis. Any questions?
❓ Câu hỏi What is the main point the professor makes about roof color choices?
A. Roof color has no significant impact on energy use in any climate.
B. The best roof color varies depending on the local climate.
C. White roofs are always the most energy-efficient option.
D. Dark roofs should be banned in all urban areas.
✅ Đáp án đúng
The best roof color varies depending on the local climate.
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
