知识贝壳
知识贝壳
所属栏目：建筑施工英语
EarlyEarth-MovingMachinesBuildingIronAgeforts,diggingcanals,makingrailroads,andconstructionmodernhighwayshaveallrequiredtheshiftingofhundredsoftonsofsoil.Asaresult,fromtheIronAgetothepresentmenhavedevisedvariousmachinesformovingearth.Oneoftheearliestearth ......（本文共 5541 字 ） [阅读本文] >>