Who is the third who walks always beside you?
When I count, there are only you and I together
But when I look ahead up the white road
There is always another one walking beside you
Gliding wrapt in a brown mantle, hooded
I do not know whether a man or a woman
— But who is that on the other side of you?

Ontem à noite, antes de adormecer, compreendi quem é o terceiro que caminha sempre a teu lado do poema de Eliot. O pronome interrogativo who é uma armadilha.