What are the keywords in the following sentence? An oven filled with three pizzas covered in cheese.
cheese, oven, pizza

What are the keywords in the following sentence? Railroad yard with trains and engines moving on tracks.
engine, train, yard

What are the keywords in the following sentence? a flock of pigeons gather in tree against clear blue sky
pigeon, sky, tree

What are the keywords in the following sentence? the gorge opens up just wide enough to allow for some large trees to grow in the wash
allow, grow, tree