prolong vs keep on

prolong and keep on both are verbs.

Word	Noun	Adjective	Verb	Adverb
prolong	No	No	Yes	No
keep on	No	No	Yes	No

As verbs, keep on is a hyponym of prolong; that is, keep on is a word with a more specific, narrower meaning than prolong:

prolong: lengthen or extend in duration or space
keep on: allow to remain in a place or position or maintain a property or feature

Other hyponyms of prolong include continue, keep, retain.

prolong (verb)	keep on (verb)
lengthen in time; cause to be or last longer	allow to remain in a place or position or maintain a property or feature
lengthen or extend in duration or space