Using て-form to indicate purpose


Someone asked me:

> どんな本を使っ **て** 日本語を勉強していますか

I'm confused about the て-form here. The only sensible translation I can think
of is:

> What kind of books do you use (in order) to study Japanese

I've not come across て-form to indicate purpose before. Is this common? How
does it differ from のに?




Your translation is perfect, but I think て is not indicating purpose. It
rather means method.

More verbatim translation is:

> **By** using what kind of books do you study Japanese?

" **By** " at the top of the sentence comes from て-form.

Related dictionary entry (quoted from デジタル大辞泉):

>
> ［接助］活用語の連用形に付く。ガ・ナ・バ・マ行の五段活用動詞の音便形に付く場合は「で」となる。形容詞、形容詞型助動詞に付く場合は「って」の形をとることもある。
>
> 手段・方法を表す。「歩い―通学する」「泣い―抗議する」

In this sentence the purpose is to study Japanese but not to use books. So you
can use のに (that indeed means purpose) to say the same as follows:

> 日本語を勉強する **のに** どんな本を使っていますか。




Your translation is perfect, but I think て is not indicating purpose. It
rather means method.

More verbatim translation is:

> **By** using what kind of books do you study Japanese?

" **By** " at the top of the sentence comes from て-form.

Related dictionary entry (quoted from デジタル大辞泉):

>
> ［接助］活用語の連用形に付く。ガ・ナ・バ・マ行の五段活用動詞の音便形に付く場合は「で」となる。形容詞、形容詞型助動詞に付く場合は「って」の形をとることもある。
>
> 手段・方法を表す。「歩い―通学する」「泣い―抗議する」

In this sentence the purpose is to study Japanese but not to use books. So you
can use のに (that indeed means purpose) to say the same as follows:

> 日本語を勉強する **のに** どんな本を使っていますか。

