So to build out a concrete, you essentially have to build twice.

所以说，用混凝土建造，本质上你得建两次。

Officials have built concrete barriers in the sea in an effort to reduce the force of waves.

官员们在海上建造了混凝土护栏，目的是减少水的冲击。

Starting around 200 BCE, the Roman Empire was building concrete structures that have stood the test of time.

从公元前200年左右开始，罗马帝国开始建造混凝土建筑，而这些建筑经受住了时间的考验。

Unfortunately, it's unclear when weather extremes will die down, and the government has repeatedly delayed projects to build concrete embankments that would prevent further erosion.

不幸的是，目前尚不清楚极端天气何时会平息，政府一再推迟建造混凝土堤坝以防止进一步侵蚀的项目。