He laughed as if this was the most preposterous idea.

"Well, you know, I had the preposterous idea that it might be the truth."

"No doubt they would believe any preposterous idea you suggested."

She didn't know what to say to such a preposterous idea.

Until now, he had been arguing theoretically about a preposterous idea.

"You'd like better so preposterous an idea that you're run out of office for a thief."

Simply, as she thought that preposterous idea, it began to take shape.

It seemed a preposterous idea, but stranger things had happened.

"He probably even told you about his preposterous idea that the plague cases and the others were started on purpose."

My mind seemed to reject the whole preposterous idea at first.