Relative clauses (That or Who)

The new cellphone (a)   I bought yesterday is very fast.

My father buys a new car (a)   is very expensive.

My teacher is a woman (a)   comes from Rusia.

The teddy bear (a)   is pink was thrown away.

The day (a)   I met him was the best day in my life.

The girl (a)   you saw yesterday is my best friend.

The boy (a)   is watching tv is my son.

Dan's sister, (a)   lives in Holywood, is an actress.

The books (a)   I borrowed were amazing!

The exam (a)   we did last week wasn't easy.