all your sentence is wrong
or
all your sentences are wrong?
all your cows/cow are/is dead.
One sentence or several sentences (plural)?
One cow or several cows (plural)?
ps. Please start your sentences with a captal letter.
Context is always important; labelling is rarely important.
(Not a Teacher)
I'm not saying it's flat out wrong, but "all your" sounds strange with singular objects. I'd only use it for plural objects:
"All your bases belong to us."
"All your cows are dead."
"All your sentences are incorrect."
Technically, there should be an 'of' between 'all' and 'your', but sometimes native speakers omit it.
Both 'All your sentences ...' and 'all of your sentences ...' are grammatically correct.
Context is always important; labelling is rarely important.