题目内容：
根据以下材料，回答题
TheBuildingofthePyramids
Theoldeststonebuildingsintheworldarethepyramids.Theyhavestoodfornearly5,000years,anditseemslikethat（1）.ThereareovereightyofthemscatteredalongthebanksoftheNile,someofwhicharedifferentinshapefromthetrnepyramids.Themostfamousofthesearethe"Step"pyramidandthe"Bent"pyramid.
Someofthepyramidsstilllookmuchthesameastheymusthavedonewhentheywerebuiltthousandsofyearsago.Mostofthedamagesufferedbytheothershasbeenatthehandsofmenwhowerelookingfortreasureor,moreoften,（2）.ThedryclimateofEgypthashelpedtopreservethepyramids,andtheirveryshape（3）.Thesearegoodreasonswhytheycanstillbeseentoday,butperhapsthemostimportantisthattheywereplannedtolastforever.
Itispracticallycertainthatplansweremadeforthebuildingofthepyramids（4）.However,therearenowritingsorpicturestoshowushowtheEgyptiansplannedorbuiltthepyramidsthemselves.Consequently,weareonlyabletoguessatthemethodsused.Nevertheless,byexaminingtheactualpyramidsandvarioustoolswhichhavebeenfound,archaeologistshaveformedafairlyclearpictureofthem.
Onethingiscertain:theremusthavebeenmonthsofcarefulplanning（5）.Thefirstthingtheyhadtodowastochooseasuitableplace.Youmaythinkthiswouldhavebeeneasywithmilesandmilesofemptydesertaround,butapyramidcouldnotbebuiltjustanywhere.Certainrnleshadtobefollowed,andcertainproblemshadtobeovercome.
回答(1)题 A．forstonetouseinmodernbuildings
B．hasmadethemlesslikelytofallintoruin
C．beforetheycouldbegintobuild
D．becausetheplansofotherlargeworkshavefortunatelybeenpreserved
E．whilebuildingthepyramids
F．theywillcontinuetostandforthousandsofyearsyet
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