I had never seen a student __________ could run so fast!
I had never seen a student WHO / THAT could run so fast!
Rebeca, __________ job as a Head Teacher gives her many headaches, went to a Alberite last week.
Rebeca, WHOSE job as a Head Teacher gives her many headaches, went to a Alberite last week.
Because I am unemployed I am currently living at my parents' house, _________ is an annoying situation.
Because I am unemployed I am currently living at my parents' house, WHICH is an annoying situation.
The book __________ I found the information is on the table.
The book which I found the information is on the table.
The Concert hall, __________ older students go to dance, is very expensive.
The Concert, where older students go to dance, is very expensive.
Santiago, __________ teaches History, hates the rain.
Santiago, WHO teaches History, hates the rain.