"I am writing a book about wine" is accepted. But there is a report in the system, from about the same time as your comment, for "i ma writing a book about wine"... which isn't. Oops?
Why is "I write a book about wine" wrong? "Pišu" is "I write", as far as I know.
because it sounds like you write one every day. but we cannot hope to teach two languages at the same time, so i added it.
It all depends on the context. If the question were "what do you do every decade?" then the answer could be "I write a book about wine." Far more likely, though, is to say, "I am writing a book about wine."
If I have this right, 'o' can be accusative or locative. Why is this locative instead of accusative? What is 'locative' about a book about wine?
"I am writing a book about wine" is accepted. There doesn't seem to be a report in the system for your answer, which means we can't see what you actually wrote, so we can't tell you what might have been the problem. It's always a good idea to use the Report button if you're fairly sure your answer was correct.
I am a little confused about the translation into English. The course suggests that the correct answer is I have been writing a book about wine, which is in past the past tense. However, I believe that 'Pisu knihu' is in the present tense. Can someone clarify please because this is not the only instance of this anomaly in the course. Thank you.
"I have been writing" is the present perfect tense. It is a still ongoing action that started some time ago.