Hi Ksenia,
Beef= Can be 'carne de boi', 'carne de vaca' or 'carne bovina'. We use the word 'carne' for all kinds of meat. Like 'carne de porco' is pork, 'carne de frango' is 'chicken meat'.
hot cocoa drink= In Brazil hot cocoa and hot chocolate are, basically, the same stuff. And the translation is 'Chocolate quente'.
Grapefruit= 'toranja' or 'toronja' are right. But we normally use just 'toranja' .
U r welcome.