Twenty million years ago, Idaho was populated by dense primordial forest.
两千万年前，爱达荷州遍布着茂密的原始森林。
《柯林斯英汉双解大词典》
2
It is hypothesized that the primordial cloud of dust and gas from which all the planets are thought to have condensed had a composition somewhat similar to that of Jupiter.
据推测，所有行星都是由尘埃和气体组成的原始云团凝聚而成，其组成与木星的组成有些相似。
3
Twenty million years ago, Idaho was not the arid place it is now. Rather, it was warm and damp, populated by dense primordial forest.