Translation:Please do not clean your shoes with a handkerchief.
"Polish" is a much closer translation of 磨く than clean, and thus should not be counted wrong
Yes, exactly! Google translate even suggests that I was trying to translate Polish--the language! And as the children of Japanese immigrants, in my experience, "磨く" does sound more like "to polish" than "to clean".
Please do not polish your shoes with the handkerchief was rejected, as I did not say "a handkerchief".
I guess Duo is convinced you would only use someone else's handkerchief to clean your shoes.
Yes, apparently it will not take either "your handkerchief" or "the handkerchief," but only "a handkerchief." This seems to be rather picky to me. More importantly, how is one supposed to tell from the provided information? [Other than guesswork and memorization.]
In one sentence, 靴を磨か can be "shine", but here Duo only allows "polish".
we shine our shoes or we polish our shoes. Both are common for this meaning.
はい！水とコットンの布とナイロンの靴下をつかいます。Seriously. You put a layer of polish on with the cotton cloth. You then put on a layer of water, then a layer of polish again. Rub with the nylon and your shoes will shine.
"don't polish the shoes with a hankie please" was marked wrong. Is the problem "hankie", or "the", or the position of "please"? Who knows... 2. "please don't polish the shoes with a hankie" - wrong. 3. "please do not polish the shoes with a hankie" - wrong 4. "please don't clean the shoes with a hankie" - wrong 5. "please don't clean your shoes with a hankie" - I guess they don't like the word hankie, then :D 6. "please don't polish the shoes with a handkerchief" - right. tsk. "hankie" is a perfectly good word.