Translation:You must finish your assignments before Friday.
I do find it strange that the English translation is "you guys". It seems to be rather specific slang! Could it be because Duo wants to emphasise the fact that it's you plural? Even though speakers of other languages often find it annoying, you singular and you plural are the same in written English.
I put the same thing, and I'm wondering if this sentence is meant to emphasize that the homework needs to be finished BEFORE Friday, meaning that on Friday the homework is already done, or if it can also mean everything is okay as long as the homework is completed by some time Friday. In the latter case, I think 'by Friday' should be acceptable as well.
1.) Geesh, I must be studying on tired eyes. Thanks for the catch. 2.) I never know how to treat this in the "Duolingo-verse." Earlier lessons seemed to want an "all" if they included "们," but now it seems hit or miss and is only a definite requirement if they have "都." IMO they should accept both since the English is less precise here than Mandarin and the English "you" can be both singular or plural.
They used to write "you all" before as the plural form of "you", actually, which is actually "y'all" without a contraction. I think that's why they had the "all" in their sentences. (I used to think that the "all" was wrong until I saw that it was based off of "y'all", which I heard was southern US slang.) The Chinese sentence should have "you" in plural due to the 你们.
You're welcome, though. I wonder what other people's opinions are. Considering that there is no "all" in Duo's translation, though, it should be OK to leave it out.