"This rice is sweet."
They would mean different things. は emphasizes what comes after it in the sentence, whereas が emphasizes what comes before it in the sentence. So when using は, you are specifically pointing out that this rice is sweet. Sweetness is the the thing that you want to specifically call attention to. If you used が instead, it would be in a situation where you were already talking about sweet things and you wanted to specifically point out that this rice is sweet.
For example, if someone asked you the question, "How does the rice taste?", you'd use a は, because you're pointing out the rice's sweetness as the answer to their question. But, if someone asked you, "Is anything in your meal sweet?", you'd use a が instead, because now you're pointing out this rice as the answer to their question.
I thought that since we're saying このご飯 that we would be drawing more attention to THIS rice in particular (in contrast to other rice) and went with が. I can see how they want to empasize the other part of the sentence, however, although I still think the form of the sentence using "ga" is valid. It just has a different meaning from what seems to have been intended by this sentence.
I mean, it can be used for 'meter', because it sounds similar. Like, it can be used for 'America' because many years ago they used kanji phonetically (america sounded for them like あめいりか, and you can read 米 like めい) and the kanji didn't have to make sence that much. Now we have kana so everything is much easier. But still, can found some single kanjis that are used weirdly.
米 is usually used for uncooked rice. It's used for America because during the Shogunate era, when Japan was making contact with western nations, the country names were written by assigning kanji that had similar readings, at least for the very first sound (much like Chinese still does). 亜 would have been assigned for 'a' but it was already being used to mean "Asia", so instead 米 was used for the next sound, 'me'. I'm not certain, but I think it's used for 'meter' for the same reason ('me').
You never put a particle before です.
このあまいごはん translates to "This sweet rice." So it is grammatically correct and you could use that ordering in a sentence, just not this one, since that isn't what the question asked for. For example, if you wanted to say, "This sweet rice is delicious," you could say, このあまいごはんはおいしいです。
I am starting to understand that translation makes it difficult to get is right. GA is always attached to the subject. In the English sentence, the rice is the subject. but the answer has a HA which means rice is a topic, not a subject. the best way I could translate literally would be: "speaking of rice, spicy exist". so the subject is spicy. If I am wrong please correct me.
甘い【あまい】 means "sweet", not "spicy" (that is 辛い【からい】).
As for the topic; it can be a lot of things, it can be the subject too.
But you just don't say 「このご飯はこのご飯が甘いです」(as for this rice, this rice is sweet) as it will be too redundant; so the redundant part is dropped : 「このご飯は
[このご飯が ] 甘いです」; in English it can't be fully dropped, but can be replaced by a pronoun: "as for this rice,
it is sweet".
If it helps you, think of it as the subject (and its particle) being there, just unspoken.
Greetings from India
Kono is an demonstrative adjective. A noun always follows it. In "This rice is sweet", "this" is an adjective that shows the quality of the rice that it is near me. Same thing in Japanese, so Kono is used: "このご飯はあまいです" (this rice is sweet).
Kore is a pronoun. It is never followed by a noun. In "This is sweet", "this" is a pronoun that replaces the noun "rice". Same thing in Japanese, so Kore is used: "これはあまいです" (this is sweet).
The crux of the confusion is that both these elements have the same word in English and many other languages. I, as a language enthusiast, actively study grammar and that's why it was easy to get my head around it.
Hope this helps :-)
Bloody 'this', 'that' and 'it is'. IMO it's really frustrating that they care so much about insisting that: - 'desu' MUST mean there's an 'it is' in your sentence - 'sore' or 'are' means you NEED to translate your sentence as 'that' - 'kore' or 'Kono' means you MUST translate your sentence as 'this'
IMO these distinctions are unnecessary, have no impact on conversation and if all you've done is dropped off a 'this/that' (and used 'the') instead then it shouldn't matter. It's just a 'gotcha' rather than me actually getting these things wrong IMO.