What are the keywords in the following sentence? traffic jam along highway that left hundreds of vehicles stranded .
hundred, leave, strand

What are the keywords in the following sentence? big pot of flowers in front of the town hall
flower, front, pot

What are the keywords in the following sentence? time lapse of clouds moving over a metropolitan city on a sunny day
city, cloud, lapse, move

What are the keywords in the following sentence? a gloved scientist fills silver cylinders with natural gas
cylinder, fill, gas