What are the keywords in the following sentence? silhouette of uneven mountains seen during the day
day, mountain, silhouette

What are the keywords in the following sentence? young students talking in a classroom during break
break, classroom, student

What are the keywords in the following sentence? players surround opening football player during the comprehensive winner on saturday
player, saturday, surround

What are the keywords in the following sentence? nurse and doctors in a hospital
doctor, hospital, nurse