From which of kennedy's speeches does the often quoted line "ask not what your country can do for you, but what you can do for your country" come?

It was JFK's inaugural speech.

Explanation:

On January 20, 1961, John F. Kennedy was sworn in as the thirty-fifth President of the United States. He gave his inaugural speech and concluded with this famous line that defined a generation. Kennedy's speech was, above all, a call to American citizens, and especially to America's youth, to participate in public service.  

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