Translation:You have come
A long time ago, English used to use "be" for some verbs in perfect and "have" for others, pretty much like French, Dutch, German et al.
At some point, this was lost and all verbs use "have" as their perfect auxiliary. You see the perfect formed with "be" sometimes in Shakespeare and things of similar antiquity. The only example I can think of from modern times is an archaic phrase I've seen on church signs at Easter: "He is risen." No one would say that these days. It's always "he has risen/gone/come/arrived/flown/swum/eaten/written/sunk/changed/etc...
Also, Americans tend to use the perfect a bit less than the rest of us Anglophones. To me, this sentence is perfectly natural ... apart from the complete lack of context that is typical of this course.
The "he is risen" on church signs isn't old grammar. It's an emphasis on the continuing nature of Jesus Christ constantly being in a state risen from death. (That sounds very clunky, but it's hard to explain otherwise).
To answer RudolfJan, "you did come" and "you have come" would both be used in American English. Have would very recent past, like just arrived recent, whereas did could be recent or longer ago. That may be why Duolingo is using the have version here, to distinguish between -me- and -li- tense markers.
"You've come" is something I hear semi-regularly. I'm fairly certain "you have" is more correct than "you did", but I can't quite remember the point of grammar here.
The problem with comparing English to Dutch when trying to work out whether the translation is correct is that you do use some verbs differently.