新视野大学英语听说教程3听力原文及答案

icaandEurasia.Theseepisodesalsocausedgreat\rmigrationsofanimalsandplants.Andyet,theearthremained.\rTheearthalsosurvivedgreaterchanges,onesthatcausedmassextinctionsofanimals.\rDuringasix-to-eight-million-yeartimeperiodaround380millionyearsago,only300species\rgroupswereleftinexistence.Andstill,theearthremained.Itwould'vesurvivedifonly250or\r200groupshadlived,oreven100.\rSowhatshouldwedowhenwearetoldthattheearthwilldie?Well,weprobably\rshouldn'tlisten.Theearthwillsurvive.We,ontheotherhand,maynot.Andso,itisinour\rbestinteresttoconserveresourcesanddefendourselvesagainstnaturaldisasters.\r1.Whatisthespeakertalkingabout?\r2.Whatcausedgreatmigrationsofanimalsandplants?\r3.Howmanygroupsofspecieswereleftaround380millionyears\rago?\r4.Whatshouldweworryaboutmost?\r5.Whatshouldwedefendourselvesagainst?