Question

what is the meaning of the word invoked as it is used in paragraph 3?
spoke in a way that caused people to feel great happiness
spent much time and effort attempting to bring about change
returned something to its former or original condition
brought something to peoples minds to make them feel a certain way

Explanation:

“Invoke”常见释义为“援引；提及（某人、某理论、实例等）”，在文中肯尼迪在演讲中提及他兄弟约翰·F·肯尼迪总统被暗杀这件事，目的是让听众产生某种情绪（不陷入种族仇恨），“brought something to people's minds to make them feel a certain way”（让某事进入人们脑海从而使他们有某种感受）符合“invoke”在此处的语境含义。

Answer:

brought something to people's minds to make them feel a certain way