Would another way of explaining the difference be to say that in English you could get the meaning of the imperfect by saying "The teacher [was] opened[ing] the door" and the indefinido as "The teacher [had] opened the door"
That is a very good point. You could also use that theory to explain the difference but there are more tenses involved in that, for example, for the "was opening" sentence we'd probably use "estaba abriendo" as well as "abría", and "abrió"(opened) is not the same as "había abierto"(had opened). What we want to emphasise in this lesson is that in English the imperfect (abría) and the indefinido (abrió) are both translated as "opened", whereas in Spanish there is the nuance of an action with a beginning and an end or not.
Thank you Inma..I think I'm starting to get it!
...this is an excellent example of what a native English speaker would have to say to convey the intention of the spanish imperfect.
Jonathan's rule is indeed sometimes helpful - i.e., if you can substitute "was/were [running]" into the sentence such that it still makes reasonable sense, then use the imperfecto. Another acceptable guideline might be to ask: "Does it fit the expression 'used to …'?" - e.g. one of the examples in this lesson could perhaps be translated: "Antonio used to eat a sandwich at midday", so use the imperfecto. However, a word of caution - these rules will not usually work with the English verb "to be" [see below >>] (and often, not with an English sentence containing "had")…. Another [for me, useful] 'rule' is that descriptions should always be rendered in the 'imperfecto', e.g. if we want to translate "the house was very big", then we should not try and invoke the "was being" rule to obtain "la casa era muy grande" >> because "the house was being very big" sounds absolutely terrible, and "the house used to be very big" changes the meaning to an incorrect one.
Sign in to submit your answer
Don't have an account yet? Join today
Test your Spanish to the CEFR standard