I stood aghast seeking an answer, and a dreadful thought entered my mind.

A dreadful thought came to him that he might have had all this trouble and anguish for no reason.

And then a dreadful, ugly thought rose inside him.

I had a sudden and dreadful thought and looked over the side.

She sat up straight, pierced by a sudden dreadful thought.

It was a dreadful thought, but no less true for its horror.

That led to a second, far more dreadful thought.

He looked at them, and a dreadful thought rose briefly in his mind like bad gas from a deep mineshaft.

And all the time my mind was full of its dreadful thoughts.

A dreadful thought occurred to me and I tried to banish it.