aquel

n. former

adj. that; yonder; former

pron. it; that one; that

n. that; it; that one

= that.
Ex: It is important to know what police or fire responses are triggered by alarms and how that reaction can be aborted and the alarm silenced.
----
* aquella = the one.
* aquello que se sale de lo normal = unconventional, the.
* aquellos = those.
* aquellos que = those who.
* de aquel entonces = of that day.
* en aquel entonces = at the time, the then + Nombre, by this time, at that time, in the course of events, during the course of events, back then.
* en aquella época = at that time.
* en aquellas ocasiones cuando = on occasions when.
* en aquellos casos = in those cases.
* en aquellos casos en los que = in those cases where.
* en aquellos tiempos = at the time, the then + Nombre, by this time.
* en aquel momento = at the time, the then + Nombre, by this time, at that time.
* por aquel entonces = at the time, about that time, by this time.