Original perfumes have alcohol as solvent that dries/evaporates very quickly from skin. Original perfumes are more long lasting if applied on pulse points.
Copy perfumes have polysorbate 20 (aka t20) as solvent that takes few minutes to dry from skin. In copy, after spraying, your skin will remain wet for long (at least 5 minutes or more). Copy perfumes are more long lasting if applied on clothes. Copies are usually more strong smelling than original ones. Plus, they never smell the same as original.