"We eat his rice."
Translation:Nosotros comemos el arroz de él.
I do not think this is a good example for the chapter. I think one would always say "Nosotros comemos su arroz", so you do not really use a preposition in this sentence.
Gender doesn't apply to "su". the "de él" is grammatically incorrect. The phrase should read "Nosotros comemos su arroz" as igb stated above.
"de él" is correct grammar. [él ≈ "he"/"him"] "de el" would be incorrect, and must be contracted to "del" [el ≈ "the"]
It's stating that it was "his rice" as opposed to rice that you purchased. If I was at a restaurant and took the rice from my boyfriends plate, I would be eating his rice. If I the rice was served on my plate I would be eating rice or my rice. So this sentence is perfectly fine. If you skipped "his" then I agree that it should be incorrect. They put it there for you to learn how things like this are said. I, of course, did it incorrectly. :)
Because in English it would translate to "We eat the rice of his" It just makes more sense than "We eat rice of his"
i put nosotras comemos arroz de él and wrong. why must hve "el" arroz =(
De él is different to del because él means 'he' whereas el means 'the', so no, you do not contract de él to del.
I do think it's a tad unnecessary to have nosotrAs here, though, but a minor thing. It confused me to begin with but I suppose it got me thinking about feminine pronouns more than I usually do, being male.
I wrote comemos su arroz and it was right but nosotros comemos arroz el de lets us know if it is a boy or girl and is more detailed and specific