Costs remain high: green steelworks are still two to three times more expensive to build than the conventional kind.

成本仍然很高：绿色钢厂的建造成本仍然是传统钢厂的两到三倍。

Storz also wants to know how mice are finding food on top of a barren, rocky volcano, thousands of feet above the highest green plants.

斯托兹还想知道老鼠如何在一座贫瘠的岩石火山顶寻找食物，其山顶比最高的绿色植物高出数千英尺。