問(もん)題(だい) mondaiな naの noは wa彼(かれ) kareが ga時(じ)間(かん)通(どお)り() jikandooriに ni来(く)る() kuruかどうか kadoukaだ da。 The question is whether he comes on time. Literal Problem [copula-な] [nom-の] [topic-は] he [subj-が] on-time [to-に] comes [whether-かどうか] [copula-だ]. 問題なのは uses explanatory の — 'the thing that's the problem is...' 時間通りに ('on time, as scheduled') uses ~通り ('in accordance with') with adverbial に. punctualityproblem-solving~かどうか (whether or not)~のは (nominalized topic)~通り (in accordance with)
問(もん)題(だい) mondaiな naの noは wa彼(かれ) kareが ga時(じ)間(かん)通(どお)り() jikandooriに ni来(く)る() kuruかどうか kadoukaだ da。 The question is whether he comes on time. Literal Problem [copula-な] [nom-の] [topic-は] he [subj-が] on-time [to-に] comes [whether-かどうか] [copula-だ]. 問題なのは uses explanatory の — 'the thing that's the problem is...' 時間通りに ('on time, as scheduled') uses ~通り ('in accordance with') with adverbial に. punctualityproblem-solving~かどうか (whether or not)~のは (nominalized topic)~通り (in accordance with)