Input: Identify the most salient words:

there are very large herds of sheep on a big field

Output: field
herd
sheep

Input: Identify the most salient words:

like an angel flying through the storm clouds

Output: angel
cloud
fly

Input: Identify the most salient words:

the study of organisms and their environment

Output: environment
organism
study

Input: Identify the most salient words:

field of dried herbs with white and yellow flowers in the wind dried of summer

Output:
field
herb
wind