I have a brother. + He works in Fukuoka. I have a brother who works in Fukuoka.
I have a cat. + It has blue eyes. I have a cat which has blue eyes.
先行詞が人 ：who, that 先行詞が人以外 ：which, that
This is the car. + I bought it yesterday. This is the car (which) I bought yesterday.
She is the girl. + I met her yesterday. She is the girl (that) I met yesterday.
目的格の関係代名詞は省略できる。（接触節) 所有格は範囲外。