Al-sarf science is one of the most scientifically accurate and rich in branches. Because it depends on the one accent and how the changes happened inside this science (from an event associated with time or not associated). The people who create this science and were deep made a tough rule to can out of these sentences without reason. The aim of this research is to declare (The Impossible Phenomenon in the Preference Name) and this study is separated into two chapters:
Section one: it’s content of (Preference) in the base books and the scientists of linguists and the rules that authorized building in the name of Preference.