Input: Identify the most salient words:

water being shot in the air from a fountain

Output: fountain
shoot
water

Input: Identify the most salient words:

an astronaut drifting in space is rescued by a space shuttle orbiting earth

Output: astronaut
earth
orbit
shuttle
space

Input: Identify the most salient words:

commuters waiting for the metro at the metro station

Output: metro
station
wait

Input: Identify the most salient words:

tourists on the bow of a ship being pulled by tug

Output:
bow
pull
ship
tourist
tug