Spanish language Q&A Forum

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?

¡Qué ________ sois vosotras dos! How aggressive you two are!(HINT: "peleón" = masculine for aggressive)… why is the answer peleonas?

Are ´con tal de que´and ´a condición de que´ interchangeable ?

Hello,

I am really confused, why abrir is irregular?

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.

On two occasions the text moved on before I could submit my answers and on another occasion it didn't let me submit an answer as I had maybe pressed a key which triggered the "Not sure about that one?" response.