Haber - Hay in the past

Question

I need some help sorting out the imperfect from the preterite.

I'm okay with use of había to denote past existance: e.g. Había leche en el refigerador.

My text book tells me that hay is very rarely used in the preterite but I am having trouble getting my mind round the difference between:

(a) Hubo un ataque nuclear anoche. (Text book says use preterite) (b) Había una araña debajo de me cama esta mañana. (Text book says use imperfect)

It is the "esta mañana" that I'm tripping up on. As "esta mañana" is a delineated time segment why is hay in the imperfect?

Answer 1

(a) Hubo un ataque nuclear anoche. The preterite is correct here because the action took place and ended last night. It's factual.

(b) Había una araña debajo de mi cama esta mañana. As opposed to other mornings. Or instead of a spider it could have been something else. Hence, you need to use the imperfect. Also, the fate of the spider has not been established.

An example using both tenses:

Había una araña debajo de mi cama esta mañana y la maté con el zapato (and I killed it with my shoe). The subordinate sentence is in the preterite because the action of killing the spider took place and ended in the past. No more spider.

I hope this makes sense.

Many thanks. This is a much better explanation than the one my text book gives. - J_G_Duff, Sep 21, 2012