What are the keywords in the following sentence? head grown into a tree
grow, head, tree

What are the keywords in the following sentence? jet fighter performing aerobatic flight at the airshow
fighter, flight, perform

What are the keywords in the following sentence? construction could begin as soon as late this year with the project completed
begin, construction, project

What are the keywords in the following sentence? view to the sea down steep narrow cobbled street in quaint old village
cobble, sea, street, view, village