Los modales perfectos (modal + have + participio) sirven para especular, deducir o criticar sobre el pasado: cosas que ya no puedes cambiar pero sobre las que opinas. He must have missed the train (deducción segura), She can't have known (deducción negativa), You should have told me (reproche), I needn't have worried (hice algo innecesario). Es una de las áreas donde más se nota el salto a C1-C2, porque el español lo resuelve con subjuntivos que no se traducen palabra por palabra.
Qué expresa cada uno
must have = seguro que pasó · can't/couldn't have = seguro que no.
might/may/could have = quizá pasó.
should have = reproche/lamento · needn't have = era innecesario pero se hizo.
Ejemplos
ENThe ground is wet — it must have rained.
ESEl suelo está mojado — debe de haber llovido.
ENYou should have called me.
ESDeberías haberme llamado.
ENI needn't have brought an umbrella.
ESNo hacía falta que trajera paraguas.
Needn't have vs didn't need to
ENneedn't have done = you did it, but it wasn't necessary.
ESneedn't have done = lo hiciste, pero no hacía falta.
ENdidn't need to do = it wasn't necessary (usually you didn't do it).
ESdidn't need to do = no hacía falta (normalmente no lo hiciste).
El error típico del hispanohablante
Siempre have + participio, nunca "of": should have gone, no "should of gone".
Para deducción segura en pasado usa must have, no "must be": he must have been tired.