Narrator: Listen to part of a lecture in an environmental science class. Professor: Today we're going to talk about a surprising source of pollution: the humble cow. Cattle farming, especially for beef and dairy, has a significant environmental impact. When cows digest food, they produce methane, a greenhouse gas that is over 25 times more potent than carbon dioxide at trapping heat in the atmosphere. In fact, livestock accounts for about 14.5 percent of all human-induced greenhouse gas emissions. But there are solutions. Some farmers are experimenting with changing cattle diets. For example, adding seaweed to feed has been shown to reduce methane emissions by up to 80 percent. Other approaches include breeding cows that produce less methane, or using methane-capturing technology on large farms to convert the gas into energy. While these methods are promising, they face challenges. Seaweed is not always available in large quantities, and changing farming practices can be costly. Still, researchers emphasize that reducing methane from cattle is crucial if we want to meet global climate targets.
❓ Вопрос What is the main topic of the lecture?
A. The nutritional benefits of seaweed for cattle
B. The environmental impact of cattle and possible solutions
C. The history of livestock farming in the United States
D. The economic challenges of small-scale farming
✅ Правильный ответ
The environmental impact of cattle and possible solutions
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