To be confused.
to puzzle, perplex, baffle, bewilder (somebody); to afflict by being complicated, contradictory, or otherwise difficult to understand
To mix up, muddle up (one thing with another); to mistake (one thing for another).
To mix thoroughly; to confound; to disorder.
To perceive differences.
To distinguish something as being different from something else; to differentiate.
To perceive, recognize, or comprehend with the mind; to descry.
To detect with the senses, especially with the eyes.