I thought 大きな was incorrect but it looks like it is legit!
大きな is very similar to 大きい! But 大きな can be use to describe non physical things, like 大きな問題 - a big problem!
Does this rule follow over to other -na adjectives like 小さな?
Only 小さい and 大きい can also be na adjectibes, as far as i know.
[romaji] Sono ookina kousaten wa sukoshi abunai desu.
I wrote その大きな交差点は少し危ないです。and was marked wrong for having "は" instead of "が". Yet, は is the correct answer above. Reported, obviously. I love being marked wrong for the correct answer over and over again. It's what makes Duo so much fun. /snark
Is there a reason I can't use ちょっと instead of すこし? I know that ちょっと is more informal, but is there something about this sentence that means it has to be formal?
I agree, "chotto" is so much more natural to me. I submitted an error report.
[Edit: そのおおきなこうさてんはちょっとあぶないです was accepted for me.]