The Grand Holtel has closed. We spent three weeks there one summer.
The Grand Hotel, where we spent three one summer, has closed.
My neighbour is learning the guitar. He used to be a singer.
My neighbour, who used to be a singer,is learning the guitar.
Our cousins often come to stay with us. Their parents travel a lot for work.
Our cousins, whose parents travel a lot for work, often come to stay with us.