Oneshot and the Chapters have completely different scenes?????!

If you read the both of them,you definetly noticed that the basic story is same,but the scenes are totally different...
I'm asking why?????

It seems like you are new to these kind of things. The oneshot serves as a "test" to see if a story with such a plot would be popular/good/well received. If it is then it will be serialized into the magazine. Usually the oneshot has changes made to the author "serialized version" for whatever reason. If you want to know more about the manga industry I suggest you go check out Bakuman. Go check out the oneshots for Nurarihyon no Mago, Naruto and other manga. They workout the same way. A oneshot isn't serialized right away though, I think it took Nurarihyon one year.
I'm not completely right nor do know the specifics of how this system works, but this explaination should be good enough for you.
Also sometimes people just make oneshots, as oneshots (not for serialization) kind of like a short story.
Hope I helped.

Edited by MrFeatherFang, 06 July 2012 - 08:37 PM.

Yes, MrFeatherFang right. Sometimes there is even a oneshot that has a title, characters, and plot different from the serialized version. For example "Try! Try! Try!" (Yotsuba&! oneshot) have different title and character design from the serialized version.

Ahh,I get it now...
Thank you guys very much!!!
^^ :3