TOEFL Listening: ETS-TOEFL听力机经 - 4B4B48H4W3QD48EWP$

What is the main purpose of the lecture? A. To broaden students' understanding of an astronomical concept B. To discuss the significance of some constellations to ancient cultures C. To introduce students to a recent decision the IAU made D. To examine the controversy over the exact number of constellations