Listen to part of a lecture in an environmental science class.
Today we're going to discuss the concept of 'urban heat islands' and some strategies to mitigate their effects. Urban areas tend to be warmer than surrounding rural areas because of the abundance of concrete and asphalt, which absorb and re-emit heat. Additionally, waste heat from vehicles and air conditioning units contributes to the temperature rise. One effective mitigation is increasing green spaces, such as parks and green roofs. These provide shade and release moisture through evapotranspiration, cooling the air. Another approach is using cool pavements that reflect more solar energy and absorb less heat. These can be lighter in color or made of special reflective materials. A third strategy involves altering building designs to improve natural ventilation and reduce reliance on air conditioning. However, implementing these measures requires careful planning and investment. Not all solutions are suitable for every city, depending on climate and existing infrastructure. For instance, green roofs may be less effective in very dry regions where water is scarce. So, while urban heat islands pose a significant challenge, a combination of strategies tailored to local conditions can make cities more livable.
❓ Pregunta What does the professor suggest as a limitation of using green roofs to mitigate urban heat islands?
A. They are too expensive to install in most cities.
B. They may be less effective in regions with limited water.
C. They do not provide enough shade for pedestrians.
D. They require constant maintenance during winter months.
✅ Respuesta correcta
They may be less effective in regions with limited water.
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