Prometheus '( ) was miraculously restored after the bloodthirsty eagle ate it everyday.

Haphaestus， god of fire, fasten Prometheus to a steep cliff by a never-failing chain, and sent a bloodthirsty eagle to peck at his liver everyday.

That the author mentions the old Romans is ______. A: To compare the old Romans with today's people B: to give an example C: to show human beings in the past know nothing better D: to indicate human beings are used to bloodthirsty