if i attack a shady spectacles to a temporary uunit, what happen

It works normally — the Temporary unit becomes a copy of your chosen friendly unit, and it still dies at the start of your next Beginning Phase.

Shady Spectacles' attach effect replaces the unit's copyable traits (Name, Type, Tags, Cost, Domain, Rules Text, Might — Rule 477.1.b.1.a). But Temporary is not a copyable trait: it's a status/characteristic on the permanent, so the copy doesn't remove or overwrite it (FAQ #11745, #12414; Rule 816.3). The unit keeps whatever Temporary instance it already had — whether it was granted (e.g., Last Stand, Mirror Image) or printed on the original token — and that instance will still trigger and kill it before scoring at the start of the controller's next Beginning Phase (Rule 816.1.b).

So you get the copied stats and rules text for the rest of the turn (and through your opponent's turn, if you attached during your Main Phase), but the unit dies on schedule anyway. When it dies, Shady Spectacles detaches and stays on the board where the unit was — if that was a battlefield, it'll get Recalled to your Base at the next Cleanup (Rules 435, 435.4.a).