知识贝壳
知识贝壳
所属栏目：建筑施工英语
Twonineteenth-centuryinventionsledtoarevolutioninbridgebuilding.ThesewerePartlandcementandmass-producedsteel.Cementisthevitalingredientofconcrete,andmassconcretecanbeusedtobuildpiers,abutments(banksupports),andarchesof“artificial”stonetoanyrequiredshape.W ......（本文共 5574 字 ） [阅读本文] >>