It is sometimes referred to as a " vein" (vein) of metal ore.

它有时被称为金属矿石的“矿脉”（vein）。

A " lode" (lode) is an area of metal ore that is found in the earth.

“矿脉”(lode) 是在地球上发现的金属矿石区域。

A " lode, " then, is a large amount of metal ore that is found in a certain area.

那么， “矿脉”就是在某个地区发现的大量金属矿石。

Metal ore became ships, cars, and also combine harvesters in a single year we harvested 22.2 billion tons of biomass, just to feed us all.

金属矿石化为轮船、汽车，还有联合收割机在一年里我们仅为吃饭就收割了222亿吨生物量。

These ancient people did not have access to metal ore, so their innovations used resources they had, like shells, bones, and stones.

这些古代人无法获得金属矿石，因此他们的创新使用了他们拥有的资源，如贝壳、骨头和石头。