What are the keywords in the following sentence? on this rock i will build my church
build, church, rock

What are the keywords in the following sentence? A black and white cat chewing on a toy.
cat, chew, toy

What are the keywords in the following sentence? People walking along a concrete dock toward a large, white ship.
dock, ship, walk

What are the keywords in the following sentence? time lapse of clouds moving over deep and wide canyon with green forests and dark blue sky
forest, lapse, move