Input: Identify the most salient words:

content passengers traveling risky by roof of train while train going on the green forest at outskirts

Output: passenger
roof
train

Input: Identify the most salient words:

roads close in the mountains during winter

Output: mountain
road
winter

Input: Identify the most salient words:

the christmas tree appears in this undated image .

Output: appear
image
tree

Input: Identify the most salient words:

ferry boat at the port of crossing on the island

Output:
boat
cross
island