What are the keywords in the following sentence? website allows you to select a century and then shows the corresponding map
century, map, website

What are the keywords in the following sentence? portrait of young doctor thinking something in the hospital
doctor, hospital, portrait

What are the keywords in the following sentence? Glazed doughnuts on cookie sheet near doughnut machine.
doughnut, glaze, machine

What are the keywords in the following sentence? a herd of fighting bulls grazing near an artificial lake
graze, herd, lake