Quedarse + [gerund] vs Continuar/Seguir+[gerund]

Hola Benhur

This is one of those structures that don't really have a very accurate translation in English, therefore the most approximate one is, as we say in the lesson, "to continue to do something". 

The little difference is that when we use "quedarse + gerund" this implies "from the moment that the action starts and including the continuity of this action". I always think of the verb "mirar" to reflect this nuance with "quedarse". For example, in this sentence:

Here how I see this action is from the moment the person turns his eyes to me and maintains this look towards me. So the start of this action is when the person starts looking at me (including this very first moment)

If we use continuar, instead of quedarse:

This doesn't include the first moment he started looking - it's simply saying that he continued looking at me. But with the previous example using quedarse, the process includes a starting point. 

I hope this makes some sense.

Saludos

Inma