So "biuro" is an office and "biurko" is a desk?
I said "the bed's" and got an error that said it should be "bed is" and that I was missing a space... but duolingo generally takes contractions, doesn't it?
Not every single one is accepted automatically, clearly... added yours.
Is blisko and obok interchangeable?
No. "blisko" is just "near", "close to". It's subjective and relative. If you look at a map of a big country, you may say that City A is 'blisko' City B, and it means let's say 20 kilometres.
"obok" is "next to". So it's pretty specific.
I just wrote "near" and marker as a mistake corrected by "close to".
Must've been a bug, 'cause it is accepted.
What is the difference between "obok" and "blisko"?
I would translate obok as (right) next to and blisko as close to.
still don't understand why 'near' is not accepted in this case. I was marked wrong
"near" is an accepted answer, it should have worked. Perhaps you had a typo somewhere and got corrected to the main answer, which has "close to".