Spanish language Q&A Forum

Do I understand correctly that both tenses are possible? If so, is there a difference in meaning or are they interchangeable?

He imprimido nuestras fotografías del viaje, ¿quieres ver ________?I have printed the pictures of our trip, do you want to see some?(HINT: Choose the correct singular form.)
I don't understand why alguna is correct here and not algunas. I get that alguna can mean 'the odd one' but this test question doesn't look like the odd one, and it almost exactly matches an example in the quick lesson, where the correct form is given as algunas. 

Extremely poor designation on this question! Either Ahí or Allí should be accepted since there is no way of knowing the even approximate distance by stating "phone conversation." A phone conversation can be held between people living in the same city, in which Ahí would be appropriate, or in another country, in which case Allí should be used.

Hola Señora,

Dónde tenemos que usar SOBRE y EN por ON en español.

I have a Spanish grammar book that teaches this construction of the passive voice: ser + past participle + por... is this NOT correct? That same book does not mention using estar 

Unfortunately for me, I keep answering La instead of El and my score for the lesson is melting down.