What are the keywords in the following sentence? medieval venetian wall which surrounds the inner part of the city
city, part, wall

What are the keywords in the following sentence? man said passengers were on board when the flight turned around
board, flight, passenger

What are the keywords in the following sentence? trains stop high speed on the tracks
stop, track, train

What are the keywords in the following sentence? A Chicago Bears decorated cake with chocolate frosting.
cake, decorate, frosting