I think that we have to be cateful with "what-comes-first-and-what-comes-second" rules, especially if we want students to come up with them. The students, at least mine, tend to think not in terms of "before" and "after" but 1st, 2nd, 3rd position in a sentence. It can be misleading. They all know the SVO word order, but when it comes to questions, for example, there are poblems. I often hear that in questions the verb is first. When I ask about wh- questions they say: "Ok, sometimes the verb is second." Then I have to go through a series of examples to make them realise it's "before the subject" is what they're looking for.