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This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) the answer is unique, (iv) its answer is a continous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage

CHAPTER IV.

Signor Andrea D'Arbino, searching vainly through the various rooms in the palace for Count Fabio d'Ascoli, and trying as a last resource, the corridor leading to the ballroom and grand staircase, discovered his friend lying on the floor in a swoon, without any living creature near him. Determining to avoid alarming the guests, if possible, D'Arbino first sought help in the antechamber. He found there the marquis's valet, assisting the Cavaliere Finello (who was just taking his departure) to put on his cloak.

While Finello and his friend carried Fabio to an open window in the antechamber, the valet procured some iced water. This simple remedy, and the change of atmosphere, proved enough to restore the fainting man to his senses, but hardly--as it seemed to his friends--to his former self. They noticed a change to blankness and stillness in his face, and when he spoke, an indescribable alteration in the tone of his voice.

"I found you in a room in the corridor," said D'Arbino. "What made you faint? Don't you remember? Was it the heat?"

Fabio waited for a moment, painfully collecting his ideas. He looked at the valet, and Finello signed to the man to withdraw.

"Was it the heat?" repeated D'Arbino.

"No," answered Fabio, in strangely hushed, steady tones. "I have seen the face that was behind the yellow mask."

"Well?"

"It was the face of my dead wife."

"Your dead wife!"

"When the mask was removed I saw her face. Not as I remember it in the pride of her youth and beauty--not even as I remember her on her sick-bed--but as I remember her in her coffin."
Output:
Who was searching in vain?