Particles can be put before copula だ?

Question

In the anime Relife ep1, I met this line "酔ってた勢いでだ".

I don't know what is で here. Is it an abbreviation, dialect, or particle? Or this is a casual speech that is ungrammatical?

If it is a particle, can I do that with を,に,へ too? I know that です can be put after almost everything to make it polite, but not sure about だ.

Thanks.

Answer 1

Yes, they can. It is reasonable to think that the sentence is a cleft sentence without the subject part.

• I don't understand what のも means in 生まれたのも育ったのも京都なんですよ

The basic pattern will be XのはYだ/です, where X is a sentence and Y is a phrase. In your case, it should be something like

• (私がそんなことを言ったのは)酔った勢いでだ.
• It is by the 勢い of being drunk (that I said such a thing).

Note () part is just what I guessed, it should be replace as appropriate to the context.

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Similarly, other particle+だ are possible. A bit artificial example:

• 彼はあなたに花を贈った He sent you flowers.
• 彼が花を贈ったのはあなたにだ It was to you that he sent flowers

In case of を or へ, I suppose it is more common to drop the copula in the sentence like the example:

• 何を見てるんですか What are you watching?
• 歩いている人をだ. (It's) Walking people (that I'm watching).

Here colloquially だ and even を would be dropped (=歩いている人).