TOEFL Listening: ETS-TOEFL听力机经 - 57U6B0IOB9BBK333P$

What is the main purpose of the lecture? A. To discuss harnessing tidal energy from the ocean B. To give details about the available renewable sources of energy C. To compare advantages and disadvantages of using tidal energy as a source of energy D. To argue that tidal energy is a better source of energy than other renewable sources