Input: Identify the most salient words:

a rainbow graces the sky over a pier built .

Output: build
grace
rainbow

Input: Identify the most salient words:

A train approaching a point where tracks merge.

Output: merge
track
train

Input: Identify the most salient words:

sailors and armed force prepare to launch tiltrotor aircraft from the flight deck of the amphibious assault ship .

Output: aircraft
deck
prepare
ship

Input: Identify the most salient words:

sky and trees reflected in the late afternoon near a city

Output:
city
sky
tree