Use a proper pronoun
He's the coach of the team. I play in the team.
He is the coach of the team in which I play/where I play.
She's the teacher. She was looking for you.
She is the teacher who/that was looking for you.
Earth is a planet. The planet contains a lot of water.
Earth is a/the planet which/that contains a lot of water.
That's the boy. His father is a police officer.
That's the boy whose father is a police officer.
Is that the shop? You bought your jeans there.
Is that the shop where you bought your jeans?