TOEFL Listening: ETS-TOEFL听力机经 - MZW96B3P1NF4V15XP$

What points does the professor make about the bedrock underlying Manhattan? A. Its depth beneath the surface is the main factor when deciding where to build a skyscraper. B. It can fracture into large pieces from the weight of skyscrapers. C. It is used as an anchor for skyscrapers. D. Its depth beneath the surface affects the cost of building a skyscraper.