Almost every line here is the paired question of whether something is right or wrong, with the 는지 ending on both halves: giving a hint as to whether the answer is right, not being sure whether the word you chose is correct, not knowing whether they got it right. 틀리다 means to be wrong or incorrect. Many Korean speakers also use 틀리다 loosely where 다르다, different, is correct, which is a well-known slip and not the sense at work here.