Quote Originally Posted by oldboy
The preposition in was confused me, because in our textbooks passive structure is only considered together the preposition by or with' that is come by agent.
I completely understand your confusion. It is strange now that I think about it. You can only substitute "in" for "by" in certain situations like this one (particularly events: Ten were killed in the terrorist attack). But for now, I think it's just important that you can recognize and understand this use of "in," but not necessary for you to use it.

And now for one last correction.

Quote Originally Posted by oldboy
The preposition in was confusing me, because in our textbooks passive structure is only considered together with the preposition by or with' that is come by agent.
I'm not sure what you meant by "that is come by agent," but I think you might mean "that is decided by the agent." Or "that is connected with the agent." Maybe?