Spanish language Q&A Forum

This goes against everything else I have learned or am learning in the classroom  - I cannot remember two sets of rules.  Any correct answer should be marked as correct, whether the so-called Latin American version or  Spanish version.   There doesn't need to be only 1 correct answer.

In the example above (Es septiembre y hace calor todavía.), todavía is placed at the end of the sentence and not before/after the verb.  Is it a less common (spoken) sentence structure?

I agree with most of the replies here. The explanation seems very confusing.

I am a little confused with terminology. Are Preterite Indefinido and Preterite Perfecto the same thing? As others have highlighted, I am confused with the past perfect and preterite perfect. 

Using esquiar as an example: I skied = Yo esquié; I have skied =  He esquiado; I used to ski = Yo esquiaba; I have been skiing = Yo estaba esquiado. Am I wrong with these examples?