Confusion regarding the usage of 〜たいものだ


In the grammar exercise book for JLPT N2, I came across the following
question:

> （ ）を食べてみたいものだ。
>
> **a.** あ、このおいしそうな料理  
>  **b.** 今日はユリさんのうちで手料理  
>  **c.** 一度、その珍しい魚

the correct answer is c.

The explanation of the original grammar point said:

> 心からの希望を言う場合や一般的な希望として言う場合に使う。具体的な希望や要求を直接言うときには使わない。

From the explanation, I can see why b would not be an appropriate answer. But
I couldn't figure out the difference between a and c.




The keyword is あ ("Ah!"). In (a), the speaker is saying あ and この ("this"),
which means his desire is something that just occurred after seeing the dish.
In Sentence (c), the speaker is saying 一度 ("at least once", "some day") and その
("that"), which means he is thinking about the rare fish and saying he has
wanted to eat it at least for a while.

Please remember your book says **一般的な** 希望. As explained in the links below,
this type of ものだ is used to describe a known or general fact (including one's
longstanding hope). You cannot use ～ものだ to describe a temporary desire like
(a).

Actually, I think there are situations where (b) makes perfect sense, so it's
not 100% incorrect. But if I have to choose the most natural one in an
exercise, I can safely choose (c).

See:

  * [The meanings of ものだ](https://japanese.stackexchange.com/q/43083/5010)
  * [How to parse 親も辞書を買ってやったかいがあるってもんだ](https://japanese.stackexchange.com/q/28872/5010)
  * [Meaning of the phase: 筋ってもん](https://japanese.stackexchange.com/q/74147/5010)




The keyword is あ ("Ah!"). In (a), the speaker is saying あ and この ("this"),
which means his desire is something that just occurred after seeing the dish.
In Sentence (c), the speaker is saying 一度 ("at least once", "some day") and その
("that"), which means he is thinking about the rare fish and saying he has
wanted to eat it at least for a while.

Please remember your book says **一般的な** 希望. As explained in the links below,
this type of ものだ is used to describe a known or general fact (including one's
longstanding hope). You cannot use ～ものだ to describe a temporary desire like
(a).

Actually, I think there are situations where (b) makes perfect sense, so it's
not 100% incorrect. But if I have to choose the most natural one in an
exercise, I can safely choose (c).

See:

  * [The meanings of ものだ](https://japanese.stackexchange.com/q/43083/5010)
  * [How to parse 親も辞書を買ってやったかいがあるってもんだ](https://japanese.stackexchange.com/q/28872/5010)
  * [Meaning of the phase: 筋ってもん](https://japanese.stackexchange.com/q/74147/5010)

