The subject is omitted, because it’s the same as the topic and so too obvious to mention. You could put it in there with が if you wanted it to be explicit, I think. But it would look funny.
I’m trying to think of an example where it would be different. How about,
The students mothers finished copying down the homework that was written on the blackboard.
In that case, the topic could still be the students and the subject the mothers.
As for the students, their mothers finished… etc.
I have no idea, but my best guess is this: 写しおわっていた is not two verbs. It’s a verb (写す) with an auxillary verb (終わる). Kind of like 取り掛かる or something. 終わる could be changing the verb to an intransitive (since owaru is intransitive). That’s wrong
Therefore nothing is replacing を because intransitive verbs can’t have a direct object.
The particle も here should be もう. That’s something I’m 99% sure of. 宿題もう写し終わっていた = had already finished copying the homework.
It is definitely 終わる as an auxillary verb, but I don’t think that turns 写す intransitive. I checked this article before posting my previous response. So I still think it’s replacing を here.
Even if も should be もう, there would still be an (implied) を after 宿題, even if it was left out because of casual speech.
No, it doesn’t. Specifically, auxiliary verbs do not change the transitivity of the verb they are modifying (barring exceptions I’m unaware of).
Ex from the dictionary entry of 終る: 「本を読み終わる」 「昼飯を食べ終わる」
Awesome to know because I was totally spitballing that one.
I suppose it could just be a classic example of dropping particles because you feel like it? A quick google search got me this sentence それより、みんな僕の宿題写し終わったのかい？ so I guess you can just do that.
I’m just gonna walk out of this one at this point.
This is not correct. It is not two separate sentences that are combined, but a single sentence that uses a relative clause. Check out some examples at Relative Clauses and Sentence Order – Learn Japanese
When something that looks like a sentence ends in a plain form verb and is followed by a noun, the clause is modifying the noun.
In this case we have 「黒板に書かれた」+ 「宿題」 so the first part modifies the second. The relative clause means essentially “that was written on the board”, so combining it, this phrase means “the homework that was written on the board”.
This modifier + noun functions like a noun, so let’s simplify it and remove the modifying clause.
学生達は(宿題)も写しおわっていた。
I surrounded 宿題 in parens, because, we really know that it’s “the homework that was written on the board”, but we’re removing complexity to understand the grammar.
Now this simpler sentence looks more like a single sentence, if we translate literally, it would be:
(学生達は the students) (宿題も also the homework) (写し copy) (おわていた had finished)
or “The students had finished copying also the homework”
Without context, the 「も」is hard to translate. Where did this example come from? Had the students already copied something down? Was something else written on the board? Japanese relies heavily on context, and taking sentences out of that context can make the meaning ambiguous. Let’s pretend for a moment that instead of 「も」it uses the particle 「を」:
学生達は宿題を写しおわっていた。“The students had finished copying the homework”
If you understand this simpler sentence, let’s put the modifying clause back in:
学生達は黒板に書かれた宿題を写しおわっていた
we get:
The students had finished copying the homework that was written on the blackboard
I bolded the modifying clause and the noun it modifies in both English and Japanese so you can see the relationship between the two better.
I do have a question though. Is it ambiguous which predicate 黒板に is attached to or would it always be understood to be part of the relative clause? i naturally read it that way (attached to the relative clause) but I don’t know if it always works like that.
It could be “The students copied (the homework that was written on the blackboard).”
or
“The students copied (the homework that was written) to the blackboard.”
But from knowing how classes work… usually the homework gets written on the board and people copy it to their notebooks. So the second sentence, while possible, can probably be disregarded.
