slab with ribs turned-up

例句：

1. 1. The engineer used a slab of concrete to build the foundation.
   工程师用一块混凝土板来建造地基。
2. 2. The carpenter cut a slab of wood for the door.
   木匠为门切了一块木板。
3. 3. The builders laid down several slabs of asphalt before starting work.
   建筑工人在开始工作前铺设了几块沥青。