"I am eating, you are drinking."
Translation:Ich esse, du trinkst.
I used "Ich esse, sie trinken" and got it wrong (assuming the plural you) :(
Plural you would be ihr trinkt.
Formal you (whether singular or plural) is Sie trinken with capitalised Sie.
But since Duo generally ignores capitalisation (even for languages where it's important, such as German), the sentence Ich esse, sie trinken should have been accepted as a translation.
why not "Ich esse, ihr trinkst."
ihr and trinkst with -st don't go together.
Much like "I is" or "you am" doesn't work in English. Each pronoun has its own verb form and you can't just pick one at random.
du trinkst is fine (if you're speaking to one person).
ihr trinkt is fine (if you're speaking to several people).
du trinkt or ihr trinkst or du trinke or ihr trinken or any other variation is simply wrong.