尽管我没想过，但是事实已经很明显，有时候我们已经接近了危险的边缘，快要耗尽了像铜，锡和银这样普通的原材料。

I hadn't either, but apparently we're perilously close in some cases to running out of common things like copper, tin, and silver.

youdao

金，银，铜，铁，锡，铅。

Gold, silver, bronze, iron, tin, lead.

youdao

金，银，铜，铁，锡，铅。

Only the gold, and the silver, the brass, the iron, the tin, and the lead.

youdao