When "di" is combined with the articles "il, lo, la, gli, i" the results "del, dello, della, degli, dei or delle" can have one of two roles. They can express an indefinite quantity like some (Io mangio delle mele), or ownership like of the (il cane delle ragazze). Source: Duolingo
my comment: No, because, ownership is stated here, as "di+lo = dello" which, means "of the" not "from the" "Il cibo dello squalo è il pesce." - "The food of the shark is the fish." I hope it make sense.
I wrote "the food for the shark is the fish" and it said I was correct.
This app was going great till prepositions. They need a clear lesson. This has more to do with sentence structure than it does word translation! Basically from what i get, food of the aka cibo dello ....translates into a 3rd person possesive not really a preposition. This is just catagorized all wrong. This should have been taught with il mio etc.......
At the beginning of the lesson there is a hint (under 'explain') that explains this. All the information needed to do these lessons is here, as long as one takes the time to read them.
" Some and 's When di is combined with the articles il, lo, la, gli, i the results del, dello, della, degli, dei or delle can have one of two roles. They can express an indefinite quantity like some (Io mangio delle mele), or ownership like of the (il cane delle ragazze). "
The algorithm of the program recognizes that "the food of the shark" is the same thing as "the shark's food" , but not all nouns can be used as adjectives to describe the same thing and the program cannot know which will work. For example, "the dog of the boy" is the same as "the boy's dog", but "the boy dog" could be misinterpreted as meaning "the male dog" and would not be used. Try reporting "shark food" as an alternate.
The article "il" is used also to indicate a category or species, in which case English would not use the article "the". http://italian.about.com/od/grammar/a/italian-definite-articles.htm
We really DO need a lesson on sentence structure, huh? If only Duolingo provided that :( Anyway, a noun followed by a preposition and then another noun implies a contraction, making "il cibo dello squalo" into "the shark's food". If you wanted to say "the food for the shark", it would be "il cibo per lo squalo" instead.
that isn't the sentence on offer. the subject is 'the food' not 'the fish'. there is a reason that sentences have subjects. the subject is what is being talked about. it may be the important center of whatever conversation is going on, italians know what they are talking about and can easily formulate your sentence if that is what they want. (il pesce è il cibo dello squalo.) didn't happen here.