Which sentence is written in passive voice? As I said these words I busied myself among the pile of bones of which I have before spoken. It seemed to have been constructed for no especial use within itself… “But I must first render you all the little attentions in my power.” We continued our route in search of the Amontillado.

It seemed to have been constructed for no special use within itself…

Explanation:

There are two types of voices when it comes to the English grammar and these are the "passive voice" and the "active voice."

"Passive voice" means that the recipient of the verb's action is the "subject." This is opposite to that of the active voice wherein the subject is the one which acts upon its verb.

The subject above is "It" and it is the recipient of the verb "have been constructed."

So, this explains the answer.