All at once a horrible thought came into her head.

A horrible thought had occurred to me with full force.

Horrible thoughts of death, and blood, have been with me all day.

Horrible thought, but suppose she was just living with him for his money?

A horrible thought of a new sort crossed his mind.

It seemed as though they were both inspired at the same time with some horrible thought.

"That is too long a story, for a horrible thought has just occurred to me."

It's a horrible thought, but you do have these thoughts.

Then the horrible thought struck me that here on Earth it wouldn't matter.

She was glad - she'd had a horrible thought about what would happen if one didn't get built.