Yep, sounds right to me. But then, I would consider the "then" here as basically an 'and so'. That is, I don't think of it as "afterwards"; I think of it like "ah, well, okay then, I'll eat your fries!". But of course, Duo wouldn't accept that much additional verbiage. :-)
Come on, think about it. Like, Americans call chips fries. But when my friend Steve cooks something, he fries it. If a French person wrote "il frites la dejuner", they would be marked wrong for good reason. The drop down menu for fries would still give him both meanings of the word in French though. The drop down menu gives the list of all possible translations for a word, not all contextually correct ones. It's all about context.