"¿Abres la caja, por favor?"
Translation:Can you open the box, please?
The "tips" section for this lesson specifically talks about how Spanish doesn't use "can you" or "will you" for requests like English. I think they are giving the best translation of the intent rather than a literal translation, which is what I imagine a professional translator would do.
Actually, a request can be a command. It is the same tense regardless. Using 'please' is simply good form.
I do not think this is a command though. That would be:
Open the box, please. Abre la caja por favor.
This is in question form. A command would be a statement.
¿Me abres la caja?, por favor. ¿Puedes abrirme la caja?, por favor
If I am standing with a border guard or customs agent and he/she says, "Open the box, please?', they are being polite but it's not optional, it is a polite command. So DuoLingo is just messing with us to require the unwritten, implied aspect of a command and not excepting a straight translation. I have reported it, the meaning is the same, in English or Spanish. I wonder if the DuoLingo English Course is so inflexible? Open the box or get a beat down! This is not grammar in either language, it's now delving into semantics and voice inflections. They should accept the simple translation and offer the aternative, more emphatic version for consideration. I really enjoy DuoLingo, but clearly there are some programmers throwing in some inflexibility, just to be annoying.