I will give explanations for each below.
Mr. John can use Japanese dictionary without doing Japanese homework.
One wrote Chinese characters without remembering new Chinese characters.
Mr. John brushed his tooth without sleeping last night.
Mr. John helps without reparing the bicycle.
Seeing above, 1,2 and 4 seem to have contradiction in meaning. For example, as for 1, Mr. John will not use Japanese dictionary if he don't do Japanese homework. I think 3 has no such contradiction.
But frankly I don't think this type of question to be good. For all of them can't be wrong in strict meaning. As for 1, it can happen that Mr. John use the Japanese dictionary without doing homework, like writing Japanese letter to friend.
If possible, I want to know the explanation given by the teacher when you got..：P