What are the keywords in the following sentence? a large jet airplane parked on a runway with people surrounding it
airplane, park, surround

What are the keywords in the following sentence? An airplane parked in an airport letting off its passengers.
airplane, let, passenger

What are the keywords in the following sentence? The train engine proceeds down the tracks between trees on both sides.
engine, side, tree

What are the keywords in the following sentence? residents in neighborhoods will come together tuesday as the city celebrates event .
celebrate, event, resident