Questions 18 to 20 are based on the
following passage. At the end of the passage, you will be given 15 seconds to
answer the questions. Now listen to the
passage.
According to the speaker, what were the beliefs of the Greek philosophers based upon
A．How the natural world was described in Greek mythology. B．What they observed directly. C．The writings of philosophers from other societies. D．Measurements made with scientific instruments.