What are the keywords in the following sentence? morning mist on the field near trees
field, mist, tree

What are the keywords in the following sentence? many passengers travel on an electric tram
passenger, tram, travel

What are the keywords in the following sentence? Above a grassy area lies a wide, darkening sky with heavy clouds and one lone airplane.
airplane, area, cloud, sky

What are the keywords in the following sentence? the famous church emerging as the morning sun breaks through an icy mist over lake
break, mist, sun