What are the keywords in the following sentence? the belfry is a medieval bell tower containing bells .
bell, contain, tower

What are the keywords in the following sentence? teacher talking to students at the school
school, student, teacher

What are the keywords in the following sentence? surgeons operate on a patient
operate, patient, surgeon

What are the keywords in the following sentence? A pizza that has pepperoni, olives, onion, bell pepper, and mushroom.
olive, onion, pepper, pizza