TOEFL Listening: ETS-TOEFL听力机经 - K4DG1419VJMW6K3PP$

What is the main purpose of the lecture? A. To discuss similarities in howEarth's Moon and Io originally formed B. To compare and contrast Jupiter's four Galilean moons C. To explain why Io differs so greatly fromEarth's Moon D. To demonstrate how tidal forces affect Jupiter