Listen to part of a lecture in an environmental science class.
Professor: Now, many people assume that recycling is always the most environmentally friendly option for managing waste. However, this is not always the case. Consider the life cycle of a product, from raw material extraction to manufacturing, transportation, use, and final disposal. Recycling does reduce the need for new raw materials, which is good, but the recycling process itself consumes energy and water, and can produce pollution. For example, recycling aluminum cans requires only about 5% of the energy needed to produce new cans from bauxite ore, so that's clearly beneficial. But for some plastics, the energy and resources used to collect, sort, and reprocess them may be nearly as high as producing virgin plastic, especially if the plastic is contaminated or of low quality. In such cases, incineration with energy recovery, or even landfilling, might have a lower overall environmental impact. So the key is not to generalize, but to analyze each material and local infrastructure to determine the best option.
❓ 質問 What is the professor's main point about recycling?
A. Recycling is always the most environmentally friendly waste management method.
B. The environmental benefits of recycling depend on the material and the process.
C. Aluminum recycling is not worth the energy it consumes.
D. Incineration is always better than recycling for plastics.
✅ 正解
The environmental benefits of recycling depend on the material and the process.
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
