Input: Identify the most salient words:

on the third day we explored a city

Output: city
day
explore

Input: Identify the most salient words:

the lakes are joined by a series of waterfalls

Output: lake
series
waterfall

Input: Identify the most salient words:

teachers working with students on computers in a classroom

Output: computer
teacher
work

Input: Identify the most salient words:

the cover of the edition of author

Output:
author
cover
edition