to but I don't know why that is not like also in the introduction but here they have the sentence New York is a city right New York is a city this one and you're asked to predict these two words and if you now compare birth to what xl9 does if so the context is is a city and you're asked to predict New York what birth does is it simply masks out the two words and says here please fill in these two words now this translates to the kind of objective being separated in the two words such that the prediction of York here is completely independent