What are the keywords in the following sentence? the blue sky is reflected in the glass of an office building
building, glass, reflect, sky

What are the keywords in the following sentence? The tall spire of the building has a clock on it.
building, clock, spire

What are the keywords in the following sentence? divers entering the sea from the boat
boat, diver, sea

What are the keywords in the following sentence? balloons of various colours floating up the sky
balloon, colour, float, sky