esto/eso/aquello/ello

Question

Hello, could esto and aquello suit in these sentences ?If not, when can I use esto and aquello ? and when musn't I use ello ?Muchas gracias.

Answer

Hola Lilou
We sometimes use "esto" as "this thing/idea" the same way we use "eso", but it is more common to use "eso". For example:

Carlos está muy triste y eso/esto me preocupa. 
Carlos is very sad and this/that worries me.

Using eso would be more common.
Aquello has the same function as esto and eso but you'd be referring to something/an idea further away in time. For example:

Mi marido me abandonó hace años y aquello me afectó mucho.
My husband left me years ago and I was very affected by that.

Ello, as explained in the lesson, is a more formal "that" than "eso" (or esto/aquello).
I hope this helps
Saludos
Inma