Reviewing the preliminary thesis is the second step. In this example you'll notice that the preliminary statement is a little bit loose, a little broad. This is not unusual, and it's okay. It suggests too much information, but at least there is something with which to work.
In the example, the two-part question has both a "what" and a "how" component. The preliminary thesis briefly answers the "what" component, makes a credible observation regarding "why", and then suggests a hypothetical answer to the "how" component.
So, where did the "why" come from: that wasn't part of the original question? The interesting thing about questions is how often they lead to others. The important thing to note here is that an answer to an unasked question is a good indicator that something needs to be revised. And perhaps it's in the question itself. Sometimes a research question needs revising before the preliminary thesis can be revised. How about, something like this:
Revised Research Question: Why is the expanding Chinese economy exerting so much pressure on global oil markets and how will it affect the debate between corporate America and environmentalists over drilling in the Arctic National Wildlife Refuge?