Spanish language Q&A Forum

The examples make sense of using, ex: tuviera, because the subject “had” something in the past. However, I’m confused by the test question because I don’t see a reference to the past. The sentence is “I hope i have a son by the time im 33.” I understand Ojalá triggers the subjunctive but I don’t see the connection to the last and therefore don’t understand why “tuviera” was the correct answer. I only selected it because it was the only subjunctive response. 

!No me encuentro/no encuentro   las llaves del coche! is the test item.

The correct answer is reported to be no encuentro.  
Encontrarse is said to be used when "surprised to discover something".  I interpreted the exclamation marks as indicating surprise at discovering I was unable to find the keys.  I was probably overthinking it, ?verdad?

If querer que is a subjunctive because it expresses wants, why is the negative also subjunctive? It expresses "not wants". Or is it because that technically also counts as a want? I remember reading that if you have a negative of a subjunctive it becomes an indicative