What are the keywords in the following sentence? lilly pad and flower in a pond
flower, pad, pond

What are the keywords in the following sentence? airplane approaching the airport for landing
airplane, airport, landing

What are the keywords in the following sentence? A man is driving a digger and moving some dirt around in a yard
digger, dirt, drive, yard

What are the keywords in the following sentence? Sheep and lamb under a tree in a pasture.
pasture, sheep, tree