Listen to part of a lecture in an environmental science class. The professor is discussing the role of wetlands in flood prevention. (Professor) "Now, many people think of wetlands as wastelands, but they actually provide crucial ecosystem services, especially in flood control. When a river overflows, wetlands act like natural sponges. They temporarily store excess water and slowly release it over time. This reduces the peak flow downstream and minimizes the risk of flooding in urban areas. However, in the past century, over half of the world's wetlands have been drained for agriculture or development. This has led to increased flooding in many regions. For example, the 1993 Mississippi River flood caused billions in damages, partly because wetlands that once absorbed floodwaters had been removed. So, restoring wetlands is not just about biodiversity—it's a cost-effective strategy for disaster mitigation. Engineers are now designing 'green infrastructure' that mimics natural wetlands to manage stormwater in cities."
❓ Câu hỏi What is the main point the professor makes about wetlands?
A. A. Wetlands are primarily valuable for their biodiversity.
B. B. Wetlands help reduce flooding by storing and slowly releasing water.
C. C. Wetlands should be drained for agricultural development.
D. D. The 1993 Mississippi flood was caused by excessive rainfall only.
✅ Đáp án đúng
B. Wetlands help reduce flooding by storing and slowly releasing 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
