音标: 英 ['keɪsən] 美 ['keɪsən]
1. However, in areas where the bedrock is deep and covered by glacial sediment, in those cases, it's very difficult to build tall buildings because you need to root those buildings either into solid rock or build concrete abutments called caissons that can support tall buildings.
然而 在基岩位置较深 并被冰川沉积物所覆盖的地区 像这种情况 就很难建高楼 因为要么得深入地底以基岩为地基 要么只能用混凝土墩台 即沉箱 来支撑高楼