听力音频：
L1
讲座
1. What is the main purpose of the lecture?
To argue that tidal energy is a better source of energy than other renewable sources
To discuss harnessing tidal energy from the ocean
To give details about the available renewable sources of energy
To compare advantages and disadvantages of using tidal energy as a source of energy
2. Which of the following is mentioned in the passage to imply that the use of tidal turbines hasn’t been popular for a very long time?
They have only been at the discussion stage of development.
The ocean was too corrosive for the machines.
They were too similar to windmills， which were not very reliable.
The development of appropriate methods was severely insufficient.
3. Why does the professor mention density of water and wind?
To emphasize that wind energy is better than tidal energy
To point out that slow water currents generate relatively significant energy
To discuss the efficiency rate of the energy source
To begin a comparison between wind and tidal energy
4. According to the professor, why are tidal fences better than tidal dams?（多选题）
Less environmental damage
The use of rotors
Lower utilization of ocean sediment
Cheaper cost
5. In the lecture, the professor describes the advantages of tidal turbines. Indicate
whether each of the following is part of advantages of tidal turbines.
Their blades cause negligible damage to marine life.
They can harness the ocean as an energy source.
They do not ruin the natural landscape.
They will create many jobs in the future.
Using sonar sensor can reduce marine life’s fatality.
6. What does the professor imply about tidal turbines?
The cost of installing tidal turbines will continue to increase as time goes by.
The technology to create tidal turbines has not yet fully been developed.
They are hard to maintain because they are difficult to see.
Their use is somewhat unrealistic now but will be the benign option in the fliture.
