In fact, the word " petroleum" literally means " rock oil" .

实际上，" 石油" 这个词字面意义上指的就是" 岩层里的油" 。

So far, Bissell's enterprise seemed to promise success, yet the great problem still remained: how could he obtain this rock oil in amounts large enough to make his enterprise a practical one?

至此，Bissell 的事业似乎有望成功， 但仍然存在一个大问题：他如何才能获得足够数量的这种岩石油， 使他的事业切实可行？