French translation of 'not to know which is which'
not to know which is which
ne pas savoir lequel (laquelle) est lequel (laquelle)
⇒ Even the twins' teacher doesn't always know which is which.
Même le professeur des jumeaux n'arrive pas toujours à savoir lequel est lequel.
Translation of not to know which is which from the Collins English to French Dictionary