It will wash away and so you got to pick the right materials in order to build a bridge.

它可能会被水冲走,之后人们就会选择更好的材料,以造出了更为坚固的桥

耶鲁公开课 - 生物医学工程探索课程节选

For example, one thing that could happen is that you build it up with wood and clay, you pick the wrong material for a bridge, and it will not stand up to the forces of nature.

例如,其中的一个问题是,选择了木头和粘土作为造桥的材料,你就选错了材料,这座桥难以与自然力相抗衡

耶鲁公开课 - 生物医学工程探索课程节选

So you build it with a material like silver and gold, and then you encounter the problems of society that your bridge might get stolen because somebody thinks they have a better use for silver and gold than your bridge.

但如果你用金或银这样的材料,你又会面对新的问题,你的桥会被偷走,因为有人认为金和银有比造桥更好的用途

耶鲁公开课 - 生物医学工程探索课程节选