Los campesinos han ido a la colina rejected for not having se.
me too -- irse is normally used for going FROM a place ; ir for going to a place ... reported
Now this is truly bizarre .... a few minutes later the suggested translation no longer uses 'se' .... was someone listening ? :-)
Why is "al cerro" incorrect?
It's just another missing translation.
the 'correct answer (and my error)" was given as "You missed a word.
Los campesinos se han ido a la colina." But the 'correct answer above also lacks "se"
Another correct solution: "Los granjeros se fueron al monte."