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1、外语下载中心http://down.tingroom.comLesson1Wecanreadofthingsthathappened5,000yearsagointheNearEast,wherepeoplefirstlearnedtowrite.Buttherearesomepartsoftheworldwhereevennowpeoplecannotwrite.Theonlywaythattheycanpreservetheirhistoryistorecountitassagas--legendshandeddownfromon
2、egenerationofstory-tellerstoanother.Theselegendsareusefulbecausetheycantellussomethingaboutmigrationsofpeoplewholivedlongago,butnonecouldwritedownwhattheydid.AnthropologistswonderedwheretheremoteancestorsofthePolynesianpeoplesnowlivinginthePacificIslandscamefrom.Thesaga
3、softhesepeopleexplainthatsomeofthemcamefromIndonesiaabout2,000yearsago.Butthefirstpeoplewhowerelikeourselveslivedsolongagothateventheirsagas,iftheyhadany,areforgotten.Soarchaeologistshaveneitherhistorynorlegendstohelpthemtofindoutwherethefirst'modernmen'camefrom.外语下载中心h
4、ttp://down.tingroom.com外语下载中心http://down.tingroom.comFortunately,however,ancientmenmadetoolsofstone,especiallyflint,becausethisiseasiertoshapethanotherkinds.Theymayalsohaveusedwoodandskins,butthesehaverottedaway.Stonedoesnotdecay,andsothetoolsoflongagohaveremainedwhenev
5、enthebonesofthemenwhomadethemhavedisappearedwithouttrace. Lesson2Why,youmaywonder,shouldspidersbeourfriends?Becausetheydestroysomanyinsects,andinsectsincludesomeofthegreatestenemiesofthehumanrace.Insectswouldmakeitimpossibleforustoliveintheworld;theywoulddevourallourcro
6、psandkillourflocksandherds,ifitwerenotfortheprotectionwegetfrominsect-eatinganimals.Weowealottothebirdsandbeastswhoeatinsectsbutallofthemputtogetherkillonlyafractionofthenumberdestroyedbyspiders.Moreover,unlikesomeof外语下载中心http://down.tingroom.com外语下载中心http://down.tingro
7、om.comtheotherinsecteaters,spidersneverdotheleastharmtousorourbelongings.Spidersarenotinsects,asmanypeoplethink,norevennearlyrelatedtothem.Onecantellthedifferencealmostataglanceforaspideralwayshaseightlegsandaninsectnevermorethansix.Howmanyspidersareengagedinthisworkono
8、urbehalf?OneauthorityonspidersmadeacensusofthespidersinagrassfieldinthesouthofEngland,andheestimatedthattherew
