「～ようか・～まいか」の後の正確な表現はどれでしょうか？


新完全マスタN2文法に、この問題があります。

> 「親に本当のことを言おうか言うまいか（ ）。」  
>  a) わからない b) 3日も考えている c) 関係ない

どうして (b) が正解ですか、また (a), (c) はどこが間違いですか。




「～おうか～まいか」is used when describing a situation where you are weighing two
opposing options (an action and an inaction, to be precise), and it is
followed by a verb phrase that denotes or implies serious consideration or
deliberation.

c) 関係ない ('is irrelevant') is an obviously wrong choice, since, for one thing,
its meaning does not involve any kind or amount of thinking.

The ill-suitedness of a) わからない ('not know') is much subtler, but I believe
it's due to the fact that the state of not knowing/わからない does not necessarily
imply that you have put some serious thought into a matter at hand; you can
not know whether you should tell the truth or not tell the truth as well
without debating the question as after debating it.

Although a) わからない might not be outright ungrammatical here (the resulting
sentence would be perfectly comprehensible to me), it has a risk of failing to
meet (what I take to be) the requirement that 「～おうか～まいか」 must be used with a
verb phrase that at least implies some deliberation.

Therefore, b) 3日も考えている, which clearly pass that test, is the best choice.




「～おうか～まいか」is used when describing a situation where you are weighing two
opposing options (an action and an inaction, to be precise), and it is
followed by a verb phrase that denotes or implies serious consideration or
deliberation.

c) 関係ない ('is irrelevant') is an obviously wrong choice, since, for one thing,
its meaning does not involve any kind or amount of thinking.

The ill-suitedness of a) わからない ('not know') is much subtler, but I believe
it's due to the fact that the state of not knowing/わからない does not necessarily
imply that you have put some serious thought into a matter at hand; you can
not know whether you should tell the truth or not tell the truth as well
without debating the question as after debating it.

Although a) わからない might not be outright ungrammatical here (the resulting
sentence would be perfectly comprehensible to me), it has a risk of failing to
meet (what I take to be) the requirement that 「～おうか～まいか」 must be used with a
verb phrase that at least implies some deliberation.

Therefore, b) 3日も考えている, which clearly pass that test, is the best choice.

