Spanish language Q&A Forum

One of the options for a mini kwiz question, ""Suspendió el examen, no porque ________ sino porque ese día no se sentía bien." As I understood it, no porque could be used with either subjunctive or indicative and not change the meaning. Why isn't "no porque no iba a estudiar" an option along with the other two examples (which were subjunctive).

I am a bit confused here. Below are two responses which I got wrong. In both cases the "hint" is that it is a "future idea". So why should one of them be indicative and the other subjunctive? "Even if you don't want to" I put in the subjunctive because there seemed to be a bit of doubt, and that was marked wrong. "Even if you do extra hours" I put in the indicative because it seemed that that was definitely going to happen.

I think this is a very complicated and nuanced piece of grammar so I would appreciate some help, thank you.

PS I tried to include a screenshot of my answers but the system wouldn't let me.

Why do you use Un before the "jugador de fútbol"

"el pulque lo sirven en las pulquerias" why do we use "lo" in this sentence 

¿Podría ser correcto usar ambas verbos en el pretérito indefinido para decir algo diferente? 

Por ejemplo "cuando vine a casa, ví el nuevo coche" en vez de "cuando venía a casa, ví el nuevo coche", para decir que lo ví inmediatamente después de que hubiera llegado (una acción cumplida, no interrumpida). 

Eso me parecería lógico y algo similar sí se puede usar en inglés, pero  ¿tiene sentido o es correcto en Español, o hay una forma distinta de decir algo así?

Espero que lo haya explicado suficiente claro... Muchas gracias.