Listen to part of a lecture in an environmental science class. Professor: So we've been discussing renewable energy sources, and today I want to focus on tidal power. Unlike solar and wind, tidal power is highly predictable because it depends on the gravitational pull of the moon and the sun, which follows a regular cycle. However, there are significant challenges. The most common method is building a tidal barrage, which is essentially a dam across a bay or estuary. When the tide comes in, water flows through the barrage, spinning turbines to generate electricity. But barrages can disrupt local ecosystems, blocking fish migration and altering sediment flow. An alternative is tidal stream generators, which work like underwater wind turbines. These are less invasive, but they require strong, consistent currents to be efficient. For example, the Pentland Firth in Scotland has powerful tides and is a promising site. Yet, even there, maintenance is costly due to harsh marine conditions. So while tidal power offers reliability, we must weigh its environmental impacts and high costs. Any questions?
❓ คำถาม What is the main reason the professor mentions the Pentland Firth in Scotland?
A. To give an example of a place where tidal stream generators are not efficient.
B. To illustrate a location with strong currents suitable for tidal stream generators.
C. To argue that tidal barrages are more effective than tidal stream generators.
D. To point out a site where environmental damage has already occurred.
✅ คำตอบที่ถูกต้อง
To illustrate a location with strong currents suitable for tidal stream generators.
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