Input: Identify the most salient words:

tree in a patch of ferns

Output: fern
patch
tree

Input: Identify the most salient words:

the aurora borealis lights up the sky above a city

Output: aurora
city
light
sky

Input: Identify the most salient words:

students in this school are forced to study in toilet

Output: school
student
study

Input: Identify the most salient words:

There is some blue tape on the wall of this bathroom

Output:
bathroom
tape
wall