Must a relative clause with な adjective be ended with な rather than だ?


In my opinion, the usage of だ is already correct in the following sentence.
But someone in my other questions said it is incorrect.

For example,

  * 映画を見ることが好きだ女性は私の妹です。The woman who likes watching movies is my younger sister.

  * 使い方が便利だ電気機は何ですか。 What is the electric appliance that is handy to use?

For the sake of completeness and comparison, I provide relative clauses with a
verb, i-adjective and noun as follows. I think they are also correct.

  * a verb: 映画を見ている女性が誰ですか。Who is the woman watching a movie?

  * i-adjective: 物価が安い町に住みたいです。I want to live in a town whose living cost is cheap.

  * noun: ジェットさんが２０歳だ映画を見ています。I am watching a movie in which Mr. Jet was 20 years old.

Must I change every だ to な in the given examples above? Please correct me if
it is wrong.




Yes, you do have to change it.

It is ungrammatical for だ to appear at the end of a relative clause. If you
need to have a (present-tense) copula at the end of a relative clause, it must
be changed to either な or の. Which of these it changes to will depend on the
noun attached to it---some turn into into な (like 好き or きれい), some turn it
into の (like 普通 or 緑), and some can turn it into either な or の (like 特別).

> この映画が好き **だ** → 好き **な** 映画(を見る)  
>  この花は緑 **だ** → 緑 **の** 花(を摘んだ)

The former group is where the term "na-adjective" comes from. Which group a
given word falls into isn't really predictable. [(See this question for more
detail)](https://japanese.stackexchange.com/q/920)

However, only だ must be changed in relative clauses. Past-tense だった can remain
as it is in a relative clause.

> この映画が好き **だった** → 好き **だった** 映画(を見る)




Yes, you do have to change it.

It is ungrammatical for だ to appear at the end of a relative clause. If you
need to have a (present-tense) copula at the end of a relative clause, it must
be changed to either な or の. Which of these it changes to will depend on the
noun attached to it---some turn into into な (like 好き or きれい), some turn it
into の (like 普通 or 緑), and some can turn it into either な or の (like 特別).

> この映画が好き **だ** → 好き **な** 映画(を見る)  
>  この花は緑 **だ** → 緑 **の** 花(を摘んだ)

The former group is where the term "na-adjective" comes from. Which group a
given word falls into isn't really predictable. [(See this question for more
detail)](https://japanese.stackexchange.com/q/920)

However, only だ must be changed in relative clauses. Past-tense だった can remain
as it is in a relative clause.

> この映画が好き **だった** → 好き **だった** 映画(を見る)

