What are the keywords in the following sentence? A jet airplane high in the sky right after takeoff.
airplane, sky, takeoff

What are the keywords in the following sentence? unmanned spacecraft flies into the shadow of bodies with heliocentric orbit and astronomical discovery .
body, orbit, spacecraft

What are the keywords in the following sentence? a dead tree in the middle of a field with mountains behind it
middle, mountain, tree

What are the keywords in the following sentence? map of the southern colonies including us state .
colony, map, state