What are the keywords in the following sentence? paper lanterns are floating in water during the festival
float, lantern, water

What are the keywords in the following sentence? The couch in this room is covered with a sheet.
couch, cover, room

What are the keywords in the following sentence? A train is arriving at the station for passengers.
arrive, passenger, station

What are the keywords in the following sentence? islamic structure where military commander was said to have ascended to heaven .
ascend, commander, say, structure