Spanish language Q&A Forum

I understand your explanations perfectly, but I was surprised to learn that it was correct to use "mitad" and "medio" interchangeably when discussing physical space.

It seems to me that way back when I was first learning those concepts, I was told that medio meant middle and and mitad meant half, and that it was an error to confuse the two. Is this a case of one of those "errors so common among native speakers that now it's not wrong anymore" ? Or was I taught incorrectly to begin with?

Thanks for the insight!

I always equate 'impersonal' with 'passive', as they seem to express the same thing. And, I've always used 'se' to express passive. So using third person is new to me, and I'm confused by this lesson and a question Kwiziq asked me to translate: 

'They took ages to build the hospital'

 among the choices were:

Han tardado mucho en construir el hospital (correct)

Se han tardado mucho en construir el hospital (incorrect)

Can someone explain why the second one is wrong.

Here are two other similar examples I found on Kwiziq that relate to this:

Tardaron mucho en construír los apartamentos = It took a long time to build the apartments.

Se tardó mucho en construir este hospital = It took (them, whoever built it) a long time to build this hospital.