"Is this rice?"
I am native speaker but this 个 sounds weird to me.
If I am asking about a single grain, I would say 这 粒/颗 是米吗？Other forms, other classifiers but 个 is never an option.
If I am using a demonstrative way without specifying the quantity (as in the English sentence) , I would say 这是米吗？, 这些是米吗？
The issue is Duolingo hasn't taught any classifier other than the generic 個 so far.
They have taught 飯 tho, so they really should have used 米飯 to teach rice. :/
I've worked on the presumption that Mandarin make the same distinction that Cantonese makes of, 米 being raw husked uncooked rice, for 飯 being cooked rice, (and 禾 being unhusked rice) Because if it does there would be a difference between the two.
Hi Keith, what is the difference between 这是米吗 and 这些米吗？ 这些 implies plural so it means 'Are these grains rice?'
这些米吗？is not good sentence. We need 是 in the middle.
这是米吗? and 这些是米吗？are basically the same. The different choices of demonstrative pronoun just refer to a single unit or a single category of things, versus multiple units/categories. The singular/plural concept here is only a contextual expression, and is not tied with the noun, as in English. If you see a single grain of rice, you should not use 这些; but if you see a pile of grains of the same type, you can use 这 (refering to a single type) or 这些 (referring to the number of grains). Conversely if you see several grains of different types, 这些 is more suitable.