on, in
She was born (...) July.
She was born in July.
The meeting starts (...) 9:00 AM.
The meeting starts at 9:00 AM.
The keys are (...) my bag.
There are keys in my bag.
We met (...) the weekend.
We met on the weekend.
He is waiting (...) the bus stop.
He is waiting at the bus stop.
He is (...) the door.
He is at the door.
We usually go hiking (...) Sundays.
We usually go hiking on Sundays.
There is a beautiful painting (...) the ceiling.
There is a beautiful painting on the ceiling.
They arrived (...) night after a long trip.
They arrived at night after a long trip.
She lives (...) a small village near the mountains.
She lives in a small village near the mountains.
The train will arrive (...) platform 3.
The train will arrive at platform 3.
The documents are (...) the folder on your desk.
The documents are in the folder on your desk.
I left my jacket (...) the back of the chair.
I left my jacket on the back of the chair.
She is looking (...) us (...) top of the building.
She is looking at us on top of the building.
We are (...) a hotel. They were (...) the bus stop.
We are in a hotel. They were at the bus stop.