H. G. Wells's great dramatic novel The Time Machine is classified as science fiction simply because it takes place in the future.
Conclusion
This classification is inappropriate. i.e. The Time Machine should not be classified as science fiction.
Evidence (because)
The Time Machine has a quality that science fiction generally lacks (compelling characters worth caring about).
Evaluate
The argument core here is very simple:
If a book has a then inappropriate quality that genre X → to classify the book generally lacks as part of genre X
The hard part is finding those elements. The word But is a pivot indicator that means we're starting to hear the Author's Argument. However, we might hear Conclusion then Support. We might hear Support then Conclusion.
The first claim after But is "this classification is inappropriate". The word "inappropriate" is an opinion indicator and this claim feels like an "I disagree" rebuttal, both of which suggest that this is the Conclusion.
The next word is "because", which is a support indicator (f.a.b.s). This confirms that the first claim after But was indeed the Conclusion.
When conclusions have pronouns in them ("this classification is inappropriate"), we need to import the referenced language. "Classifying Time Machine as sci-fi is inappropriate". We can interchangeably switch in other normative language like 'should not' for 'inappropriate'. "We shouldn't classify Time Machine as sci-fi."
What's the support for this conclusion? What is it about Time Machine that doesn't match sci-fi? It has compelling characters, which sci-fi generally lacks.
Goal
Let's find an answer that allows us to prove that Time Machine shouldn't be classified as sci-fi. Most likely it will be based on possessing a trait that sci-fi generally lacks.