Why is there plain form in this sentence?


The following examplatory sentence in the grammar section of my textbook:
どうして医者になりたいんですか。 ...医者は人を **助けるすばらしい** 仕事だからです。

It translates to (according to my textbook): Why do you want to become a
medical doctor? ...Because medical doctor is a great job in which you help
people.

What confuses me is that in the bold part, there is no connective form like て
form or ます stem. I know plain form as a way to make a verbal expression an
attribute to the related noun. In my textbook, it is said that a plain-form-
sentence + からだ expresses the reason(s) for an event. However, is it necessary
to omit other grammatical habits like the aforementioned て and ます form for
chaining verbal expressions inside the respective clause? I just want to avoid
being confused down the road when I'm encountering such constructions in the
wild :D




> > どうして医者になりたいんですか。  
>  ...医者は人を **助けるすばらしい** 仕事だからです。
>
> It translates to (according to my textbook): Why do you want to become a
> medical doctor? ...Because medical doctor is a great job in which you help
> people.
>
> in the bold part, there is no connective form like て form or ます stem.  
>  I know _**plain form as a way to make a verbal expression an attribute to
> the related noun**_.

I think you are talking about 連体形{れんたいけい} here, and this grammar point is the
answer to your case. The modifying adjective (すばらしい) might have caused your
confusion. The noun that is modified by a relative clause can also take other
adjectives.

> 医者は〔人を **助ける** 〕〔（すばらしい） **仕事** 〕だからです。

/

> In my textbook, it is said that a plain-form-sentence + からだ expresses the
> reason(s) for an event. However, is it necessary to omit other grammatical
> habits like the aforementioned て and ます form for chaining verbal expressions
> inside the respective clause?

Yes, we say 助けるからだ to express a reason, and yes, to connect a verb with the
particle て, or a helping verb like ます, た, etc., the verb form is conjugated to
the particular form (連用形{れんようけい}): 助けてくれた, 助けます, 助けた, etc. So, this form is
not to connect to a noun. It's like the English conjunction 'and':
彼は小さいころから親{おや}を **助けて働{はたら}いた.**




> > どうして医者になりたいんですか。  
>  ...医者は人を **助けるすばらしい** 仕事だからです。
>
> It translates to (according to my textbook): Why do you want to become a
> medical doctor? ...Because medical doctor is a great job in which you help
> people.
>
> in the bold part, there is no connective form like て form or ます stem.  
>  I know _**plain form as a way to make a verbal expression an attribute to
> the related noun**_.

I think you are talking about 連体形{れんたいけい} here, and this grammar point is the
answer to your case. The modifying adjective (すばらしい) might have caused your
confusion. The noun that is modified by a relative clause can also take other
adjectives.

> 医者は〔人を **助ける** 〕〔（すばらしい） **仕事** 〕だからです。

/

> In my textbook, it is said that a plain-form-sentence + からだ expresses the
> reason(s) for an event. However, is it necessary to omit other grammatical
> habits like the aforementioned て and ます form for chaining verbal expressions
> inside the respective clause?

Yes, we say 助けるからだ to express a reason, and yes, to connect a verb with the
particle て, or a helping verb like ます, た, etc., the verb form is conjugated to
the particular form (連用形{れんようけい}): 助けてくれた, 助けます, 助けた, etc. So, this form is
not to connect to a noun. It's like the English conjunction 'and':
彼は小さいころから親{おや}を **助けて働{はたら}いた.**

