Input: Identify the most salient words:

A plane that is hanging up in the air.

Output: air
hang
plane

Input: Identify the most salient words:

time lapse with cruise ships passing by

Output: lapse
pass
ship

Input: Identify the most salient words:

a tractor collecting up bales of straw from a recently harvested field

Output: collect
field
straw
tractor

Input: Identify the most salient words:

Grey cat lying on the keyboard of a laptop as someone tries to type.

Output:
cat
keyboard
laptop
lie