4.Linh liked the waiter.He was very friendly
=> Linh liked the waiter who was very friendly
5. We broke a car.It belonged to my uncle
=> We broke a car which belonged to my uncle
6. Ba dropped a cup.It was new
=> Ba drepped a cup which was new.
7. Nam loves books.They have happy endings
=> Nam loves books which have happy endings.( do books là vật => dùng mđqh which)
8. I live in a city.It is in the north of Vietnam
=> I live in a city where is in the north of Vietnam ( do a city là nơi chốn)

4  linh liked the waiter who was very friendly .
5  we broke a car that belonged to my uncle .
6  ba dropped a cup which was new .
7  nam loves books which have happy endings .
8  i live in a city which is in the north of Vietnam .