The interpretation of the Swift GRB X-ray afterglows

We discuss the current interpretations of the {\it Swift} GRB X-ray afterglows, mainly focusing on the sharp decline at the prompt tail emission, and the shallow decay afterward, which is then followed by the conventional pre-\emph{Swift} decay behavior, and the possible X-ray flares during the latter two stages. We emphasize the role of the central engine in interpreting the GRB afterglows.