Spanish language Q&A Forum

To say "He must have closed the door.", does one simply switch to the present indicative of deber and say "Él debe haber cerrado la puerta." or can one stay with the simple conditional and say "Debería haber cerrado la puerta." and translate it into English as must or should, depending on context?

I think this issue boils down to trying to know when to translate deber as "should" or as "must". ¿Puedes ayudarme?

Is there any possibility of adding a speed control to these exercises? Once I understand the vocabulary, it'd be great to be able to progressively increase the speed for comprehension at street level.

I'm guessing that we can use other verbs of movement the same way? 

Regreso a terminar mis estudios. (I came back to finish my studies).

Corro a comprar leche a la esquina. (I'm running to buy milk at the corner (store)).

Thanks.