"I like to swim."
Translation:Ik zwem graag.
Adverb meaning "gladly", "like to", "willingly" or "please". It can't be used as a verb.
A very formal and rarely used nowadays form of "graag" is "gaarne", used in exactly the same way. You can sometimes us that word to request someone to do something in a polite way. You can still see it a lot at signs at person's houses, like "bezoek gaarne achterom" (meaning (not literally) "visitors, please use the back entrance").
okay, so " Ik graag te zwem /zwemmen" is WRONG! THEN "IK HOUD VAN TE ZWEM" is also shamefully wrong also? it says to say " IK ZWEM GRAAG" or " IK HOUD VAN ZWEMMEN" zwemmen is for jullie,wij and zij (right?) BTW is there some dutch classroom one could join around here in duolingo?