～おうと思う not allowed to be used as a question


According to The Japan Times "A Dictionary of Basic Japanese Grammar"
textbook, the grammar pattern ～おうと思う can't be used as a question. As an
example they state that you can't say あの本を読もうと思いますか。

> When the subject is not the first person, [...] the nonpast form of _omou_
> cannot be used.
>
> ...
>
> The reason why [it] is unacceptable is that _omou_ represents an internal
> feeling of the speaker alone.
>
> ...
>
> It is also to be noted that _~yō to omou_ cannot be used as a question.
>
> (p.570)

Why is this?




～うと思う can be used as a question, and あの本を読もうと思いますか perfectly makes sense to
me.

But it's also a nuanced sentence. This roundabout question is asking the
listener's wish or intention very explicitly. I feel this question form is
more often used as a [rhetorical
question](https://en.wikipedia.org/wiki/Rhetorical_question) (or
[反語](https://ja.wikipedia.org/wiki/%E5%8F%8D%E8%AA%9E) in Japanese).
あの本を読もうと思いますか sounds to me more like "Do you _really/still_ want to read the
book?" rather than simple "Would you like to read the book?"

