What are the keywords in the following sentence? the amphibious assault ship approaches the pier .
approach, pier, ship

What are the keywords in the following sentence? Someone grabs his other wrist and drags his friend upward.
friend, grab, wrist

What are the keywords in the following sentence? the staircase leads bedrooms on the first floor
bedroom, floor, staircase

What are the keywords in the following sentence? nomadic shepherds and their flocks of sheep in the mountains in the region of southeast
flock, mountain, sheep, shepherd