What are the keywords in the following sentence? clear blue sky with some clouds near horizon and sunshine over green field
field, horizon, sky

What are the keywords in the following sentence? a dense forest of young trees in winter
forest, tree, winter

What are the keywords in the following sentence? this is actually an old building built when chinese municipality was colonised by interest .
build, building, interest

What are the keywords in the following sentence? art gallery is a national museum dedicated to arts and history .
art, gallery, history, museum