that something had happened to
Tom sabia que algo havia acontecido com Mary.
Tom knew that something had happened to Mary.
Como poderíamos saber que algo havia acontecido com você?
How could we have known that something had happened to you?
Tom achou que algo havia acontecido com a Mary.
Tom thought something had happened to Mary.
Como nós poderíamos saber que algo havia acontecido com você?
How could we have known that something had happened to you?