Narrator: Listen to part of a lecture in an environmental science class. Professor: Today we're going to talk about a surprising factor in climate change: the role of forests. You might think that planting more trees is always good for the climate, but recent research suggests that in some regions, forests may actually contribute to warming. How? Well, trees absorb carbon dioxide, which is good, but they also release water vapor and other compounds. In boreal forests, for example, the dark canopy of evergreens absorbs more sunlight than snow-covered ground would, reducing the albedo effect. This means that in snowy areas, replacing bright snow with dark trees can trap more heat. Additionally, trees emit volatile organic compounds that can form aerosols, which may either cool or warm the atmosphere depending on conditions. So, while tropical forests generally have a cooling effect, boreal forests might have a net warming effect over the short term. This complicates simple tree-planting initiatives. So, what should we do? We need to consider local climate, reflectivity, and the type of forest before assuming that planting trees is always beneficial. Now, let's discuss some case studies.
❓ 質問 What is the main point the professor makes about forests and climate?
A. Planting trees in all regions is an effective way to combat climate change.
B. Forests can have varying effects on climate depending on their location and characteristics.
C. Boreal forests always cool the climate because they absorb carbon dioxide.
D. Tropical forests contribute to global warming due to their dark canopies.
✅ 正解
Forests can have varying effects on climate depending on their location and characteristics.
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
