means directly translated to
become, to get. With this meaning, the change
itself cannot be the focus of the verb. The emphasis
here is on the moment when the change is finished, and
the result is noticeable. Quedar is used only with adjectives
and relates always to persons.
as verb of changes is different from the one quedarse
that means to stay.
with quedarse = to stay, to keep
coche se quedó en España. = The car stayed in Spain.
Quedaron en no decirle
nada. = They kept not telling him