L2
讲座
1. What is the lecture mainly about?
How volcanic activity causes mountains to rise
How cycles of landform creation can be predicted
How the movement of Earth’s tectonic plates has changed over time
How two processes of landscape formation interact with each other
2. Which claims made by William Davis’s geographical cycle theory are no longer accepted by scientists?（多选题）
The uplift of mountains is a relatively quick process.
Landscape formation occurs in distinct stages.
Rivers are the main agents of erosion.
Rivers gradually make hills steeper.
3. What is the professor’s attitude toward the idea that erosion can cause mountains to rise further?
He has serious doubts about the idea.
He considers the idea similar to Davis’s theory.
He thinks that the idea is probably surprising for the students.
He believes that some scientists initially misunderstood the idea.
4. Why does the professor discuss the melting of glaciers?
To identify the source of water in many mountain rivers
To cite evidence that helped support Davis’s theory
To emphasize one result of climate change
To illustrate the effect of removing weight from part of a tectonic plate
5. What point does the professor make when he mentions that streams can deposit material in mountain lakes?
Himalayan lakes contain a particularly large amount of sediments.
Lakes often form near the steepest parts of mountains.
Mountain lakes tend to become larger over time.
Erosion does not always result in uplift.
6. What does the professor say about the monsoons?
They have contributed to the rising of the Himalayan peaks.
They are likely to weaken in the future.
They cause surprisingly little erosion.
Scientists have proof that they began 50 million years ago.
