Listen to part of a lecture in an environmental science class. The professor is discussing the concept of urban heat islands. Okay, so we all know that cities tend to be warmer than surrounding rural areas. This is called the urban heat island effect. But what causes it? Well, one major factor is the replacement of natural surfaces with materials like concrete and asphalt. These materials absorb and retain heat from the sun much more than vegetation does. Also, buildings and roads trap heat, and waste heat from vehicles and air conditioners adds to the problem. Interestingly, the effect is strongest at night, because the urban materials slowly release the heat they absorbed during the day. So, what can be done? One solution is to increase green spaces, like parks and green roofs. Another is to use reflective materials for roofs and pavements. These strategies can lower city temperatures, reduce energy consumption for cooling, and improve air quality. Now, let's consider a specific example...
❓ 문제 According to the professor, why is the urban heat island effect strongest at night?
A. Because cities continue to generate heat from traffic and air conditioning.
B. Because urban materials gradually release the heat they absorbed during the day.
C. Because there is no solar radiation to cool the surfaces at night.
D. Because vegetation releases moisture only after sunset.
✅ 정답
Because urban materials gradually release the heat they absorbed during the day.
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
