About the stomach, which of the following descriptions are correct?
选项：

A:It is the most distensible part of the alimentary canal.
B:It is divided into four regions: cardiac part, body of stomach, pyloric antrum (幽门窦)and pyloric c
C:It has two surfaces, two borders and two orifices.
D:The right concave border is named the lesser curvature of stomach (胃小弯).
E:The orifice by which the stomach communicates with the duodenum is called the cardiac orifice.