Considering the format of the lessons, how do you suggest they explain it first? There are no lectures or text books. There is a brief synopsis at the beginning of a unit, but they can't explain every strange idiom one might encounter. The explanations at the beginning of the units were only recently added. At least for those using the Android app. The only way to expose you to new material is to simply spring it on you and allow you to get it wrong once. What's the big deal? Wrong answers teach as well, if not better, than correct ones. Incorrect answers are not bad. They are part of the process. No one is judging you. Relax. Yes, there are limitations to this method of learning. But it's not an exam, it's an exercise.
This is the thing. "So-So" is very US English. In the UK So-So is never or rarely used. However "It's alright", "I'm OK" are both equivalents but are both not recognised here.
Would be cool if we got an explanation for this as "So-So" is not really part of my vocab as a native Englishman.
This is incorrect. "So-and-so" is used to refer to people: a person or thing whose name the speaker does not need to specify or does not know or remember.
"let's have so-and-so as a speaker on Tuesday".
"So-so" is used to describe something which is neither very good nor very bad: "the President is only a so-so golfer".
So-so and so-and-so have entirely different meanings.
I am normally quite accepting when I have a bit of a problem with certain translation suggestions from DL (not many - it is generally a massively useful learning tool) but feel I have to comment on this. On a previous exercise, I put (the exercise required the English translation) 'it works', for the German 'es geht!' but it was marked wrong; this time I put 'it goes' then I got the correct translation as 'so-so' or 'it works' (would you believe!); so, I asked my German cousin. He says you could use 'es geht' for: 'it works', 'it goes', or 'so-so' and various other things actually. I suppose it's a case of learning where you can. And by the way, I do understand that one often cannot accurately translate sentences word for word, but....