Question

I had at heart a strange and anxious thought. Something had happened which I could not comprehend; no one knew of or had seen the event but myself: it had taken place the preceding night.

Accepted Answer

Existía para ello una tercera causa que nadie sino yo conocía, y que había sucedido la noche antes.

Back	I had at heart a strange and anxious thought. Something had happened which I could not comprehend; no one knew of or had seen the event but myself: it had taken place the preceding night.
Front	Existía para ello una tercera causa que nadie sino yo conocía, y que había sucedido la noche antes.

I Heart Strange Anxious Thought Happened Comprehend Knew