Input: Identify the most salient words:

number painted on a concrete surface

Output: number
paint
surface

Input: Identify the most salient words:

rising moon over the city

Output: city
moon
rise

Input: Identify the most salient words:

A white door leading into a bathroom with a checkered floor.

Output: bathroom
door
floor
lead

Input: Identify the most salient words:

The old airplane has three propellers on it's front engine.

Output:
airplane
engine
propeller