阅读技巧训练(4)

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1、阅读技巧训练(4)　　　　Youarewhatyoueat.Thissayinghasprovidedscientistswithcluesaboutthedietofhominids－ourearlyrelativesof3millionyearsago.　　Studyingcarbonatomslockedupintoothenamel，tworesearchersargueagainstthewidelyheldbeliefthathominidsatelittlemorethanfruitsandleaves.SponheimerandJuliaLee－Th

2、orpoftheUniversityofCapeTown，southAfrica，reporttheirfindingsinFriday‘sScience.　　Therearen‘tmanycluesforustoknowthelifeofearlyhominids.Theshapeofhominids’teethofferedthefirstclues.Largeandflat-edgedwiththickenamel，theylookedperfectforeatingnutsandfruits，differentfromthesharpteethonewoul

3、dwanttotearintomeatwith.Thefirststonetools，whichwouldhelpineatingmeat，didn‘tappearuntilabouthalfamillionyearslater.　　Scientistshavealsofoundmarksonhominids‘teethwithpatternsverysimilartothoseontheteethofmoderndayfruiteaters.SponheimerandLee-Thorptriedanewmethod，lookingatthechemicalcomp

4、ositionofthetoothenamel.Theystudiedtheenamelforthecarbon-13.Animalsthateatgrasseshavehighercarbon-13levelsthanthoseeatingfruitsandotherplants.　　Whattheyfoundwasthattheteethofthehominidshadanin-betweenamountofcarbon-13，whichmeantnotonlytheywereeatingfruits，theywereeatingalotofgrass，oran

5、imalseatinggrasses.Thelowercarbon-13levelscouldalsocomefromeatingcertaintypesofinsects。　　Buttherearepeoplewhounderstanddifferently.Porf.UngaroftheUniversityofArkansasagreesthestudyoffersnewsuggestionsofhominiddiet，butdisagreesaboutthesuggestionthatmeatcouldexplainthelowercarbon-13level

6、s.　　Onesuggestionmightbetruethough-takegoodcareofyourteeth.In3millionyears，ascientistmightbeusingthemtofigureoutwhatyouatefordinner.　　1.Whichofthefollowingcanbethebesttitleforthetext？　　A.ProtectYourTeeth.　　B.WhattheHominidAte.　　C.WheretheHominidlived.　　D.TheFormationofToothEnamel.　　2.B

7、eforethetwoscientists‘findings，mostpeoplethoughtthathominids______.　　A.livedhalfamillionyearsago　　B.atemainlyfruitsandleaves　　C.usedtoolstodiggrass　　D.hadsharpteeth　　3.Thetwoscientists‘findingsweremainlybasedonthestudyabout______.　　A.theshapeofhominids‘teeth　　B.theteethmarksofearlyfr