L2：
Question 12 of 17
What does the professor mainly discuss?
Select 2 answers.
Methods of preventing pollution in rivers
The history of river restoration in industrialized countries □
Human activities that disturb river ecosystems □
Defining the goals of river restoration efforts
Question 13 of 17
Why does the professor mention deforestation?
To explain the growing interest in river restoration
To illustrate the impact that human activity can have on rivers
To demonstrate how animals can lose their natural habitat
To give an example of a problem that river restoration projects cannot address
Question 14 of 17
What does the professor suggest about levees?
They are expensive to build and to maintain.
They actually cause more flooding than they prevent.
They can affect the health of a river ecosystem.
They are being built in greater and greater numbers.
Question 15 of 17
According to the professor, why were some waterways lined with concrete in the 1900s?
To allow them to carry away pollutants more easily
To prevent their banks from collapsing
To reduce the effects of bed coarsening
To provide water for agricultural purposes
Question 16 of 17
According to the professor, why have many river restoration projects been ineffective?
They have taken too long to complete.
They have not received adequate funding.
It has been impossible to determine the original state of the rivers.
They were not completed with appropriate measures of success in mind.
Question 17 of 17
What does the professor say about damage to infrastructure caused by flooding?
Without levees, such damage is unavoidable.
Repairing such damage is more expensive than other restoration projects.
Most people underestimate the economic consequences of such damage.
Restoring rivers to their natural state might prevent such damage.
