What are the keywords in the following sentence? time lapse of blue skies above a lake
lake, lapse, sky

What are the keywords in the following sentence? building and road in the financial district
building, district, road

What are the keywords in the following sentence? demonstrators gather at the site of a planned speech by film writer
demonstrator, gather, site, speech

What are the keywords in the following sentence? clouds float over the mountains
cloud, float, mountain