What are the keywords in the following sentence? an astronaut drifting in space is rescued by a space shuttle orbiting earth
astronaut, earth, orbit, rescue, shuttle

What are the keywords in the following sentence? main street of small town on the coast
coast, street, town

What are the keywords in the following sentence? silhouette of a coconut palm trees during sunrise
silhouette, sunrise, tree

What are the keywords in the following sentence? air bubbles rise to the surface of the water
bubble, rise, surface, water