I typed 'Drucken es aus' and got marked wrong. Is 'Sie' not optional?
Drucken Sie is the formal imperative. You could have said "Druck es aus" as the informal imperative though.
I did too. Duo had no 'n' ...'Drucke es aus' - but my German exchange student isn't here right now to let me know if 'Drucke' is right or wrong.
Actually this is imperative form...Print It! no 'e' either...so "Druck es aus" (the "Drucken Sie es aus" is more formal. (my exchange student came back). :-)
Warum nicht "das"?
That would be 'Print that out!'. This is very similar to Duos sentence but its not the same.
Why can't you use "er" or "sie" here as if they were being used to refer to masculine or feminine objects? Z.B if you were talking about "Die Seite" could you not say "Drucken Sie sie aus"?
yes, you're right
Why is "Drucke du es aus" unaccepted but "Drucken Sie es aus" accepted?
Because that's how imperatives are formed in German:
singular informal: "druck(e) es aus!" (no pronoun used, like in English)
plural informal: "druckt es aus!" (no pronoun either)
formal (singular and plural): "drucken Sie es aus!"