noun 下载 🔗分享 基础设施，下部结构，底层结构 The supporting part of a structure (either physical or organizational; the foundation). Examples : "The old house needed repairs because the substructure, the wooden frame beneath the floor, was rotting. " 这栋老房子需要维修，因为它的下部结构，也就是地板下面的木制框架，已经腐烂了。 structure architecture building organization part 与AI对话词汇游戏阅读练习
noun 下载 🔗分享 道碴, 路基. The earth or gravel that the railway tracks are embedded in. Examples : "The train tracks felt stable because the construction crew had recently reinforced the substructure with fresh gravel. " 火车轨道感觉很稳固，因为施工队最近用新的碎石加固了道碴/路基。 material geology structure 与AI对话词汇游戏阅读练习
