ايه الفرق بين

Covered with

And
Covered in

Covered by
ارجو الرد السرع

"Covered by" generally means that the covering actually hides the thing that is covered: it would usually be an object (a sheet, a lid, a curtain) rather than a substance, that is doing the covering. "Covered by blood" is unlikely, and "covered by snow" would imply that the snow is so deep that you can't see what it is covering. "Covered by blankets" is a more likely example.
"Covered in" is more metaphorical: the covering is widely distributed over the object, but does not actually hide it. "Covered in blood" is a typical expression, and does not usually mean that every single point on the surface has blood, rather that blood is widespread over it.
"Covered with" is somewhere in the middle, and can mean the same as either of the other two.