prepositions of time and place

Sorry, John isn't here. He's ....... work.

It's a beautiful day. let's go ... the beach.

Sally's boyfriend works ... a factory.

My brother studies maths ... Manchester University.

I go ... the gym .... Tuesdays and Thursdays.

I work ... an office.

We live .... a modern flat.

It's Monday. The children are .... school.

My father is a doctor. He works ... a hospital.

Jack isn't ... home. He's with a friend.