I am confused as well. I believe, it is technically also correct. However, they argue with context here. It is much more likely that the girl is drinking her own milk than drinking someone else's milk, who is coincidentally male.
We to stick to the subject. If it's HER drinking, presume it's her milk. Unless the sentence specifically mentions a man being in the picture don't assume it's his milk. And vice-versa. For example:
"Le homme boit son biére froid." A or B?
A) The man is drinking her cold beer. B) The man is drinking his cold beer. . . .
I have some serious doubts about the validity of this English translation. In the phrase, "cold milk", "cold" is clearly an adjective describing the temperature of the milk. However, in the sentence, "The girl is drinking her milk cold", "cold" acts more as an adverb describing how the girl drinks her milk.
This may be a distinction without a difference, but it is definitely a difference. The position of "cold" changes the gist of the sentence.
For example, "The girl drinks her milk cold, and so she refuses to drink this warm milk."
This got me confused even though I already know son/sa refers to the object being possessed. Apart from the context which can be confusing sometimes (The girl drinks his cold milk doesn't seem wrong at all to me), how else can I know when it's a his or a her?
Please someone clarify the difference from 'cold' being an adverb for drinking and or an adjective to 'milk'
it was marked wrong because it is "her". The gender of the possessive pronoun or adjective has nothing to do with the speaker. You have to match the gender and the number of the thing possessed.
I know, << la fille boit sont les froid >> doesn't make any sense. But that is what I hear. Any tips on how to differentiate << son lait >> from << sont les >>