1. The new dam was a bulwark against future floods.
    新水坝是将来抵御洪水的屏障。

2. They built up an earthen dam.
    他们建起了土坝。

3. Presently, all we can do is look at mug shots and stick our fingers in the dam.
    而目前，我们所能做的就是看看罪犯的照片，并参与到构筑抑制犯罪的大坝中去。