This is the 12526th most frequent Polish word.
należały
"Belonged"
The verb 'należały' indicates past possession or ownership of the books by my grandmother.
Te książki należały do mojej babci.
These books belonged to my grandmother.
Here, 'należały' is used to specify past ownership of the keys by a particular individual.
Klucze należały do właściciela domu.
The keys belonged to the owner of the house.
In this sentence, 'należały' associates the tasks with the advanced category, conveying past classification or belonging.