托福阅读 The answer lay in a resource that unknowing Americans lands trampled ……如何翻译？

the answer 指代这篇阅读的上一段最后一句话的问题：How had they survived?
The answer lay in a resource that unknowing Americans had trampled underfoot in their haste to cross the "Great American Desert" to reach lands that sometimes proved barren.
你看的版本中句子有点错误，lands 应该是 had。
翻译：对于此问题的关键在于那些资源，当一无所知的美国想要到达新的土地（这些土地后来证明也十分贫瘠），犹豫是否要穿越“美国大沙漠”时，这些资源被无情践踏、踩在脚下。
that 从句是定语从句，修饰 resource；第二个 that 也是定语从句，修饰 lands。要更好的理解句子，可以多做一点句子分析哦。