We may not separate terumah from tahor [produce] on behalf of tamei [produce]. But if they separated terumah [thus], their terumah is terumah. In truth, they said: [Regarding] a round cake of pressed figs part of which became tamei, one may separate terumah from the tahor [figs] it contains on behalf of the tamei [figs] it contains, and likewise for a bundle of vegetables, and likewise for a pile [of produce]. If there were two round cakes [of figs], two bundles [of vegetables], or two piles [of produce], one [of which is] tamei and one [of which is] tahor, one may not separate terumah from this [one] on behalf of that [one].  Rab-bi Eliezer says: We may separate terumah from tahor [produce] on behalf of tamei [produce].