The last time I got the exact same question, it gave the correct translating of 'kwa kusoma' as 'for studying.' This time, I entered exactly that, and it will only accept 'for reading.' I like the format of duolingo, but it's so poorly edited that it's hard to use.
Just report such things. As users, we are also responsible for improvements. Since it's a free app, I guess they have limited resources.
Using what for reading? A book, lamp, table, library. Which is the object infix??
I now see that the PA noun class is locative, so presumably the infix refers to a place, such as library, unspecified. It looks as though I was the only one who didn't understand that. If so, I'm sorry for wasting your screen space!
I didn't get it either, so thanks for checking that out for us, AndyCole9!
I think the 'it' is meant to refer to a place suitable for reading, such as a library. It seems that the absence of a specified location does not excuse the use of the locative infix.