Narrator: Listen to part of a lecture in an environmental science class.
Professor: Today we’re going to talk about urban heat islands. You might think that cities are just warmer because of all the concrete and asphalt, but there’s more to it. One major factor is the lack of vegetation. Trees and plants provide shade and release moisture through transpiration, which cools the air. When we replace green spaces with buildings and roads, we remove that natural cooling effect. Another factor is waste heat from vehicles, air conditioners, and industrial processes. But here’s an interesting point: the heat island effect isn’t uniform across a city. Dense downtown areas can be several degrees warmer than surrounding residential neighborhoods with parks. This difference is most pronounced at night, because the built-up materials release heat slowly, while rural areas cool off quickly. So, when we think about solutions, planting more trees is helpful, but we also need to consider reflective materials for roofs and pavements. These can reduce the amount of solar energy absorbed. Does anyone have a question?
❓ คำถาม According to the professor, why do urban heat islands have the greatest temperature difference at night compared to rural areas?
A. A) Because cities generate more waste heat from vehicles at night.
B. B) Because built-up materials release heat slowly, keeping cities warmer.
C. C) Because trees transpire more at night in rural areas.
D. D) Because reflective materials are only used during the day.
✅ คำตอบที่ถูกต้อง
B) Because built-up materials release heat slowly, keeping cities warmer.
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
