Spanish language Q&A Forum

When is the letter "A" used in front of a verb

Hello, there is a section called "Variable Subjunctive" that has the sentence: 

no tengo un profesor que viva en madrid 

which means: 

I don't have a teacher that lives in madrid.

My question is why would this be a subjunctive, it seems like what this person is saying is a fact that he knows that he doesn't have a teacher that lives in madrid. Or maybe he's trying to say that he doesn't have a teacher that he KNOWS OF. Idk I just want to know why it's a subjunctive. thank you 

Just a query.. why is it " tenemos que conocer nuestras emociones" (no "a"), but "para poder controlar a estas" (with the personal "a") in the same sentence referring to the same object? Is this inconsistency typical of conversational speech?

Helpful maybe to think of salvo que, a no ser que, a menos que (and sin que) followed by subjunctive as implying a NOT. A conditional : Unless = If not.

Hi, why is preterite used here instead of the imperfect? The preterite implies that Ustedes no longer exist.

How can you start the lesson with "Antes de que and Antes que are always followed by the subjunctive. For example:"

Then in the last part of the lesson give examples without the subjunctive. That's the opposite of always. 

Hola Inma, busco un listo de verbs de moviemiento.  He buscado el internet.  ¿Existe un listo de estos verbos?  Gracias y que tengas una buena tarde.

Ken

Muchas gracias Silvia, Shui e Inma -

Hay otro hecho interesante [¿e importante?]:

Durante el mes de septiembre [y también en marzo], la latitud del sol [es decir su posición encima de la superficie de la Tierra] cambia más que en los otros meses [durante su viaje N>S, o S>N]. Por eso, las duraciones de luz del día están disminuendo muy perceptiblemente - por 27½ minutos durante esta semana [en Londres].